So, general problem this aims to solve - right now, outleveling content is an issue for some players, especially completionists like myself. Ouroboros is an option for replaying older content, but it comes with a couple of significant drawbacks - first, it only covers part of the content, namely story arcs and badge missions, leaving almost all one-off missions from those contacts {which are often as numerous as their arced content} unavailable, and second, it forces the player into a taskforce-level commitment, both time and teammate-wise, which can be a major issue when it comes to longer arcs. Turning off the XP is an option, but it's a very rigid and inconvenient one - having to hit a handbrake on your level progress in order to not miss much of the game's content can easily be a hassle, especially if someone wants to jump on higher-level teams or taskforces or just simply not have to worry about jumping on a tip team in Atlas and suddenly miss half the game.
The general idea is this - rather than have contacts stop giving you missions once you pass above their level, they continue to give you all of their usual missions. In instanced missions, however, the player would be exemplared to the mission's highest-available level, rather than beating on gray mobs. This is accomplished via a snippet of code that forces a MaxCombatLevel on the player. It appears in only one place, the Ouroboros introduction arc, but by all indications, it's trivial to insert into any instanced mission code, complete with a proof-of-concept I made on my home test server {unfortunately, my computer didn't handle running one very well, so testing is still limited} and theoretically, the bulk of the work might be possible to handle with some simple scripting.
This does, however, present a more design-level dilemma as well - how contacts are handled. The existing system might not mesh well with the concept, because I believe the player is introduced to contacts within their own range, and if they aren't, it would add a major random factor to who does get introduced. To add to the problem, for most of the original content, each taskset {list of one-off missions} and story arc is actually available to multiple contacts - Mind Of A King arc, for example, is available from no less than four contacts, only one of which the player normally gets introduced to. Now, the introduction part itself might easily be shortcutted by giving each of those types of contacts an IssueOnInteract flag, where simply talking to the contact introduces them to the player, but I'm not sure whether the game would allow the player to have the same arc going from multiple contacts - I haven't been able to test it, but given that game will cheerfully give you multiple identical tasksets from different contacts, it seems likely.
A solution for that might be simple from the technical standpoint - simply deprecate all but one contact for each of the arcs/tasksets. However, doing so would make a further departure from the original game, and whether that would gel with Rebirth's overall vision is a much more prickly topic. On the other hand, it would also make those contacts available for future story content instead, though if and when that happens remains unknown.
On the other hand, it also might present another QoL opportunity - content from original contacts tends to send you all over the city, often regardless of rhyme or reason. I suspect that was part of the original intent, as travel time is generally a good time to pad subscriptions. On the other hand, content, story arcs especially, tend to deal with a specific enemy group, and those groups tend to dominate specific zones. Thus, it might make more sense, universe-wise, if contacts who issue a story arc which deals with a specific group are in the zone where that group is present. Furthermore, it is possible to force the location of a mission to a specific zone, which means that, say, a player who takes on an arc dealing with the Tsoo would take it from a contact in Steel Canyon, and all the missions would {whenever possible} take place in Steel Canyon. This might also give more attention to zones that players tend to avoid - a Clockwork or Troll arc would take place in Skyway, for example, which tends to be overlooked, or drawing people to Independence Port for Sky Raider or Family content.
It would also seem to be in line with a lot of the newer content, where contacts with miniarcs would keep you in specific zones, like Graham Easton, Laura Lockhart or all of Praetorian content, really. Thus, while it might possibly not line up with the original vision, it would flow much more consistently with the way developers have been designing content in the latter years of the game.
Any thoughts?