I feel like adding a roguelike mode/cave/dungeon (not raid) is a nice idea as endgame content (not neccesarily endgame). I guess the major issue is variety, but this is a barebones suggestion as is.
I suppose a benefit is that you wont need to move around the map lol.
Maybe the Forgery will have something like that at some point...
I think we just have enough elements in wynn to patch something like this together (like the blessing system from raids), also i thought at multiple points in my playthrough that i found one of these (see: extra large caves and the grootslang resource thing which i thought was a roguelike).
The idea just came to me that this might be a thing when we inevitably dive into the nether, just feels like it fits.