Expansion Ideas: Systems, Features, and Content Types - What would you add?

[Acidblood]

Try to develop, as least once, a huge, hard donjon (instanced or not). designed for 4 or 8, with multiple paths, optionnal/secret boss, roaming patrols of trash, where mobs can link add etc., and quests tied to it. (like EQ2 donjons, or Blackrock Depths from WoW vanilla) You could go to clear only a few boss, go specifically for a quest, or to clear it all)
If people like it, great, you can make more of those, if not, well then at least they'll have tried. But I'm pretty sure it can be a huge success.

^ Definitely this! And just a general move away from Casual = Braindead FATE grind (but instanced! :/) and Hardcore = Dancing with a Boss. (MHW event is hopefully a step in this direction).

Class customisation via Traits and just generally giving every class the attention they need to make them fun, fluid, and distinct (even if this means no 'new' classes).

Systems to allow more re-use (i.e. scaling to current iLevel and rewards) of 'old' content... e.g. monthly 'savage' dungeons, weekly 'time-travel' raids / trials, some sort of progressive dungeon scaling (e.g. mythic+)

A proper (ARR/HW style) relic quest with diverse activities that can be done slowly over time (and solo / duty finder if needed).

Extreme suggestion: Drop PvP (or at least the competitive side of it) and introduce seasonal PvE leader boards for competitive dungeons / trials / raids / etc. (e.g. fastest run, fastest kill(s), least damage taken, etc.) ... duty recorder could be used to verify results and share them publicly.

[Ekimmak]

A proper (ARR/HW style) relic quest with diverse activities that can be done slowly over time (and solo / duty finder if needed).

See, while the original versions were a grind, they were also a lot of things you could do on your own over time.

There's an excessive lack of things to do while waiting for a cross-world party to fill. The relic/anima weapons were a good "spare time" thing to do, but since Eureka is also instanced, going for the Anemos equipment means forgoing any queues or grouping.