A question that I've been asking myself (now that I have more than one Level 50 participating in Incarnate Trials) is ... which Interface options are the "most friendly" with what other teammates and leaguemates have slotted?
One of the simplest bit of quick shorthand for stacking of Interface effects:
So, for example ...
Let's say that everyone in a league has attack powers that have 2s animation times (to keep the math simple for this example thought) and attack chains using those powers that produce a "just in time" recharge behavior. How many people can attack the same $Target with the same Interface slotting WITHOUT overwriting each other's Interface effects (against Minions, Lieutenants, Bosses, Elite Bosses)?
Let's have a look, shall we?
Interface options that deal DoTs have their names bolded.
The reason why DoT (Core) options are given an 8+ count before multiple attackers reach the stack limit is because the DoTs "cancel on miss" ... and with a 25% (base) chance to proc, are highly unlikely to run for their full 4s duration of DoT ticks. Therefore, the DoTs inflicted by attackers are unlikely to stack to 8 (and stay there) for any significant length of time.
By contrast, DoT (Radial) options are not only more likely to proc, with a 75% (base) chance to proc, but they're also much more liable to run their full set of DoT ticks ... particularly with Genesis: Socket T4 slotted, increasing Interface proc chances by +10%.
With Genesis: Socket T4 slotted, you start looking at no more than 2-3 people with the same DoT (Radial) slotted before they start "stepping on each other's toes" and filling the DoT stack to the limit of 8 and then (in effect) "wasting damage output" relative to alternative choices.
Then there's the "Slot & Forget" factor, of wanting to have an Interface option that you don't need to keep changing for specific Incarnate Trials.
Cognitive: Confuse is basically "always useful" in all circumstances (in my estimation), except against PToD Resistant on Archvillains/Heroes and Giant Monsters. It keeps mobs clumped together (if they attack each other) and it redirects damage AWAY FROM the league (yourself and others). Even if you've got a lone Minion, land a Confuse on them and it's "as good as a hold" for getting them to "sit still" for you while you burn down their remaining HP.
Degenerative: Max HP Debuffs are "nice to have" but will tend to only make a difference on Elite Bosses and above ranks.
Diamagnetic: ToHit Debuffs amount to "defense via offense" (or words to that effect) and are extremely synergistic with defense protection oriented build strategies (think Force Fields, Time Manipulation, Super Reflexes, etc.). Regeneration Debuffs also fall into the "nice to have" category, and against Elite Bosses and above ranks can actually yield more "reduction in damage needing to be dealt" against Big Bags o' HP than a DoT would have been able to produce, so net win for Regeneration Debuffing vs DoTs against AV/GM ranked Foes.
Gravitic: The Debuffs (lots of them!) produced by Gravitic procs are all "nice to have" but aren't always going to be "helpful" to a league. Movement Speed Debuffing (Core) sounds great ... until you need to herd clumps of mobs into ambush points (UG and TPN Trials, in particular). Special Debuffing (Radial) sounds "weird" until you realize that it's kind of like an anti-Power Boost type effect (if you're familiar with Power Boost). Best when paired with Recharge Debuffing (Time Manipulation, Ice, et al.) and/or Endurance Drain (Electric et al.) build plans and playstyles.
Paralytic: Since this option includes no DoTs, I don't think anyone touches or bothers with this one. However, for builds with PBAoE Damage Auras/Patches (Icicles, Obliterating Death, et al.) being able to rapidly stack and maintain a 4x -5% Damage Debuff on Foes using the T4 Radial could have a lot of utility for Aggro Magnet builds (Tankers, et al.). Additionally the Defense Debuff AND Damage Debuff are likely to have pretty decent Threat Multiplier factors as debuffs, making it easier for Aggro Magnets to grab and hold onto aggro more easily than just "doing more damage" (per se) with a DoT. For AoE heavy builds, especially those that can chain multiple AoEs into a crowds of clumped up Foes, the Damage Debuff factor can make a lot of difference to the amount of incoming damage that a league is taking, especially if your powers also include Damage Debuffing natively in them (Kinetic Melee, Dual Pistols: Chemical Ammo, et al.). Additionally, Damage Debuffing synergizes directly with Resistance protection schemes, effectively yielding increased (net) Resistance beyond what hardcaps would suggest as nominally possible. Needing less animation time for healing means more animation time is available for attacking(!), which in turn could yield more damage "output" from individuals than they might have produced via DoT options.
Preemptive: The primary point and purpose of the END Recovery Debuff is to synergize with "Sapper" builds that drain endurance (often Electric).
Reactive: Resistance Debuffing sounds wonderful ... until you realize that it only stacks up to 4x -2.5% = -10% ... which isn't a lot. That's comparable to 1 leaguemate nearby having Leadership: Assault buffing everyone. While "nice to have" it isn't going to be much of a tide turner. If you think in terms of -2.5% Resistance in terms of damage equivalencies (or better yet, Interface DoT ticks):
Spectral: Definitely the odd one out in this list, but it's also the only option that offers a Mez relevant to setting up Containment for Controllers. The problem is that Immobilization isn't always a desirable effect (herding mobs in UG, TPN) (pulling Nightmares out of Pink Puddles during MoM), but can be a desirable "feature" for ranged attackers who want to avoid melee.
Something that I haven't been able to test yet is if the Special Debuff effect will "magnify" the durations of Mez effects cast onto affected $Targets (by PCs and their Pets), essentially making them "vulnerable" to those Mez effects ... which can then interact(?) with the Confuse and Immobilize durations of Cognitive and Spectral Interface procs(?) to make them last longer, because Interface procs are "granted powers" that $Targets (involuntarily) cast upon themselves?
I think I can do some controlled testing on mobs in Night Ward to see if Gravitic (Radial) Special Debuff boosts Mez durations on $Targets. If it does, I can envision circumstances in which Controllers (and Dominators) will want to make use of Gravitic (Radial) to increase their lockdown capabilities.
However, the really big takeaway I want to glean from the above analysis is ... just how "team friendly" the Cognitive Interface option really is.
It's kind of like the age old question of Leadership: Maneuvers vs Fighting: Weave comparisons when it comes to softcapping Defenses.
When soloing, Weave is "better" on yield.
However, as soon as two people on a team have Maneuvers ... everyone on the team "gets Weave level" defense ... and if you're 1 of the 2 needed, it's a lot easier to find that +1 you need to meet (and beat!) the +Defense yield obtainable from Weave.
1x PC with Cognitive (Core) isn't going to be making that much of a difference, since usually only the Minions/Lieutenants will "notice" the Confuse effect (due to limited stacking potential). It'll happen "occasionally" but not often in clutch circumstances.
2x PCs with Cognitive (Core) attacking the same $Targets ... now the Confuse can start STACKING to useful degrees of Mag and start affecting Bosses!
3x PCs with Cognitive (Core) attacking the same $Targets ... the potential to Confuse Elite Bosses starts happening intermittently.
4+ PCs with Cognitive (Core) attacking the same $Targets ... things start getting "unfair" in a hurry, for your $Targets.
What makes this observation especially interesting is that Masterminds have Pets that will "inherit" the Mastermind's Interface slot when summoned (which includes zoning). So 1 Mastermind with 6 Pets can effectively "group attack" a single target as if they were Team-7 (if the Mastermind has personal attacks that deal damage) and were all slotted with the exact same Interface slot option. So a Mastermind who slots Cognitive, Diamagnetic, Gravitic, Paralytic or Spectral can deliver a "max stack" of Interface effects MUCH faster than a soloist of another archetype can.
I've had T4 Diamagnetic Core slotted on my Ninja/Time Mastermind build for a while, and it makes my ninjas SO MUCH MORE SURVIVABLE, because each ninja pet can inflict -5% ToHit Debuffs (max stack: 4) independently, vastly improving their survival rate in sustained combat, even if they scatter to attack their own $Targets.
Something I really ought to test is T4 Cognitive Core on a Mastermind, with the notion of using an "alpha strike barrage" of Mastermind+Pets to deliver 7 chances to proc Confuse in the opening salvo against a single $Target. With Genesis: T4 Socket boosting proc chances by +10% ... that means a 30% chance per hit of a Confuse proc of Mag 2 for 4.3s. With 7 ranged attacks incoming simultaneously, that ought to average to ~2 successful Confuse procs, enough to Confuse a Boss with the opening salvo.
Of course, in solo play, my preferred option is to attack from range with my Mastermind (to draw aggro) and then use Bodyguard Mode to help "soak" any incoming fire and prompt my Pets to retaliate (almost as one in response). Keeps things simpler in terms of "directing traffic" and has better outcomes when something unexpected happens (such as drawing too much aggro!).
One of the simplest bit of quick shorthand for stacking of Interface effects:
- DoTs can stack to 8 from all sources.
- All Other Effects can stack to 4 from all sources.
So, for example ...
Let's say that everyone in a league has attack powers that have 2s animation times (to keep the math simple for this example thought) and attack chains using those powers that produce a "just in time" recharge behavior. How many people can attack the same $Target with the same Interface slotting WITHOUT overwriting each other's Interface effects (against Minions, Lieutenants, Bosses, Elite Bosses)?
Let's have a look, shall we?

Interface options that deal DoTs have their names bolded.
- Cognitive: 5-6 for Confuse (Core), 10-12 for Confuse (Radial) / 8+ for Psionic DoT (Core), 2-4 for Psionic DoT (Radial)
- Degenerative: 1-2 for Max HP Debuff (Core), 4-5 for Max HP Debuff (Radial) / 8+ for Toxic DoT (Core), 2-4 for Toxic DoT (Radial)
- Diamagnetic: 1 for ToHit Debuff (Core), 2 for ToHit Debuff (Radial) / 2 for Regeneration Debuff (Core), 1 for Regeneration Debuff (Radial)
- Gravitic: 1 for Debuffs (Core), 1 for Debuffs (Radial)
- Paralytic: 1-2 for Defense Debuff (Core), 4-5 for Defense Debuff (Radial) / 4-5 for Damage Debuff (Core), 1-2 for Damage Debuff (Radial)
- Preemptive: 1-2 for END Recovery Debuff (Core), 4-5 for END Recovery Debuff (Radial) / 8+ for Energy DoT (Core), 2-4 for Energy DoT (Radial)
- Reactive: 1-2 for Resistance Debuff (Core), 4-5 for Resistance Debuff (Radial) / 8+ for Fire DoT (Core), 2-4 for Fire DoT (Radial)
- Spectral: 4-5 for Immobilize (Core), 4-5 for Immobilize (Radial) / 8+ for Negative Energy DoT (Core), 2-4 for Negative Energy DoT (Radial)
The reason why DoT (Core) options are given an 8+ count before multiple attackers reach the stack limit is because the DoTs "cancel on miss" ... and with a 25% (base) chance to proc, are highly unlikely to run for their full 4s duration of DoT ticks. Therefore, the DoTs inflicted by attackers are unlikely to stack to 8 (and stay there) for any significant length of time.
By contrast, DoT (Radial) options are not only more likely to proc, with a 75% (base) chance to proc, but they're also much more liable to run their full set of DoT ticks ... particularly with Genesis: Socket T4 slotted, increasing Interface proc chances by +10%.
With Genesis: Socket T4 slotted, you start looking at no more than 2-3 people with the same DoT (Radial) slotted before they start "stepping on each other's toes" and filling the DoT stack to the limit of 8 and then (in effect) "wasting damage output" relative to alternative choices.
Then there's the "Slot & Forget" factor, of wanting to have an Interface option that you don't need to keep changing for specific Incarnate Trials.
Cognitive: Confuse is basically "always useful" in all circumstances (in my estimation), except against PToD Resistant on Archvillains/Heroes and Giant Monsters. It keeps mobs clumped together (if they attack each other) and it redirects damage AWAY FROM the league (yourself and others). Even if you've got a lone Minion, land a Confuse on them and it's "as good as a hold" for getting them to "sit still" for you while you burn down their remaining HP.
Degenerative: Max HP Debuffs are "nice to have" but will tend to only make a difference on Elite Bosses and above ranks.
Diamagnetic: ToHit Debuffs amount to "defense via offense" (or words to that effect) and are extremely synergistic with defense protection oriented build strategies (think Force Fields, Time Manipulation, Super Reflexes, etc.). Regeneration Debuffs also fall into the "nice to have" category, and against Elite Bosses and above ranks can actually yield more "reduction in damage needing to be dealt" against Big Bags o' HP than a DoT would have been able to produce, so net win for Regeneration Debuffing vs DoTs against AV/GM ranked Foes.
Gravitic: The Debuffs (lots of them!) produced by Gravitic procs are all "nice to have" but aren't always going to be "helpful" to a league. Movement Speed Debuffing (Core) sounds great ... until you need to herd clumps of mobs into ambush points (UG and TPN Trials, in particular). Special Debuffing (Radial) sounds "weird" until you realize that it's kind of like an anti-Power Boost type effect (if you're familiar with Power Boost). Best when paired with Recharge Debuffing (Time Manipulation, Ice, et al.) and/or Endurance Drain (Electric et al.) build plans and playstyles.
Paralytic: Since this option includes no DoTs, I don't think anyone touches or bothers with this one. However, for builds with PBAoE Damage Auras/Patches (Icicles, Obliterating Death, et al.) being able to rapidly stack and maintain a 4x -5% Damage Debuff on Foes using the T4 Radial could have a lot of utility for Aggro Magnet builds (Tankers, et al.). Additionally the Defense Debuff AND Damage Debuff are likely to have pretty decent Threat Multiplier factors as debuffs, making it easier for Aggro Magnets to grab and hold onto aggro more easily than just "doing more damage" (per se) with a DoT. For AoE heavy builds, especially those that can chain multiple AoEs into a crowds of clumped up Foes, the Damage Debuff factor can make a lot of difference to the amount of incoming damage that a league is taking, especially if your powers also include Damage Debuffing natively in them (Kinetic Melee, Dual Pistols: Chemical Ammo, et al.). Additionally, Damage Debuffing synergizes directly with Resistance protection schemes, effectively yielding increased (net) Resistance beyond what hardcaps would suggest as nominally possible. Needing less animation time for healing means more animation time is available for attacking(!), which in turn could yield more damage "output" from individuals than they might have produced via DoT options.
Preemptive: The primary point and purpose of the END Recovery Debuff is to synergize with "Sapper" builds that drain endurance (often Electric).
Reactive: Resistance Debuffing sounds wonderful ... until you realize that it only stacks up to 4x -2.5% = -10% ... which isn't a lot. That's comparable to 1 leaguemate nearby having Leadership: Assault buffing everyone. While "nice to have" it isn't going to be much of a tide turner. If you think in terms of -2.5% Resistance in terms of damage equivalencies (or better yet, Interface DoT ticks):
- 10.709/0.025*1 = 428.360 ... 13.3863/0.025*1 = 535.452
- 10.709/0.025*2 = 856.720 ... 13.3863/0.025*2 = 1070.904
- 10.709/0.025*3 = 1285.08 ... 13.3863/0.025*3 = 1606.356
- 10.709/0.025*4 = 1713.44 ... 13.3863/0.025*4 = 2141.808
- 10.709/0.025*5 = 2141.80 ... 13.3863/0.025*5 = 2677.260
Spectral: Definitely the odd one out in this list, but it's also the only option that offers a Mez relevant to setting up Containment for Controllers. The problem is that Immobilization isn't always a desirable effect (herding mobs in UG, TPN) (pulling Nightmares out of Pink Puddles during MoM), but can be a desirable "feature" for ranged attackers who want to avoid melee.
Something that I haven't been able to test yet is if the Special Debuff effect will "magnify" the durations of Mez effects cast onto affected $Targets (by PCs and their Pets), essentially making them "vulnerable" to those Mez effects ... which can then interact(?) with the Confuse and Immobilize durations of Cognitive and Spectral Interface procs(?) to make them last longer, because Interface procs are "granted powers" that $Targets (involuntarily) cast upon themselves?
I think I can do some controlled testing on mobs in Night Ward to see if Gravitic (Radial) Special Debuff boosts Mez durations on $Targets. If it does, I can envision circumstances in which Controllers (and Dominators) will want to make use of Gravitic (Radial) to increase their lockdown capabilities.
However, the really big takeaway I want to glean from the above analysis is ... just how "team friendly" the Cognitive Interface option really is.
It's kind of like the age old question of Leadership: Maneuvers vs Fighting: Weave comparisons when it comes to softcapping Defenses.
When soloing, Weave is "better" on yield.
However, as soon as two people on a team have Maneuvers ... everyone on the team "gets Weave level" defense ... and if you're 1 of the 2 needed, it's a lot easier to find that +1 you need to meet (and beat!) the +Defense yield obtainable from Weave.
1x PC with Cognitive (Core) isn't going to be making that much of a difference, since usually only the Minions/Lieutenants will "notice" the Confuse effect (due to limited stacking potential). It'll happen "occasionally" but not often in clutch circumstances.
2x PCs with Cognitive (Core) attacking the same $Targets ... now the Confuse can start STACKING to useful degrees of Mag and start affecting Bosses!
3x PCs with Cognitive (Core) attacking the same $Targets ... the potential to Confuse Elite Bosses starts happening intermittently.
4+ PCs with Cognitive (Core) attacking the same $Targets ... things start getting "unfair" in a hurry, for your $Targets.
What makes this observation especially interesting is that Masterminds have Pets that will "inherit" the Mastermind's Interface slot when summoned (which includes zoning). So 1 Mastermind with 6 Pets can effectively "group attack" a single target as if they were Team-7 (if the Mastermind has personal attacks that deal damage) and were all slotted with the exact same Interface slot option. So a Mastermind who slots Cognitive, Diamagnetic, Gravitic, Paralytic or Spectral can deliver a "max stack" of Interface effects MUCH faster than a soloist of another archetype can.
I've had T4 Diamagnetic Core slotted on my Ninja/Time Mastermind build for a while, and it makes my ninjas SO MUCH MORE SURVIVABLE, because each ninja pet can inflict -5% ToHit Debuffs (max stack: 4) independently, vastly improving their survival rate in sustained combat, even if they scatter to attack their own $Targets.
Something I really ought to test is T4 Cognitive Core on a Mastermind, with the notion of using an "alpha strike barrage" of Mastermind+Pets to deliver 7 chances to proc Confuse in the opening salvo against a single $Target. With Genesis: T4 Socket boosting proc chances by +10% ... that means a 30% chance per hit of a Confuse proc of Mag 2 for 4.3s. With 7 ranged attacks incoming simultaneously, that ought to average to ~2 successful Confuse procs, enough to Confuse a Boss with the opening salvo.
Of course, in solo play, my preferred option is to attack from range with my Mastermind (to draw aggro) and then use Bodyguard Mode to help "soak" any incoming fire and prompt my Pets to retaliate (almost as one in response). Keeps things simpler in terms of "directing traffic" and has better outcomes when something unexpected happens (such as drawing too much aggro!).