Tree of Savior's developer team implemented a cool idea into their game, where a certain class (Squire) can repair people's equipment beyond its maximum numbers. So if your gear averaged 50/50, an armorsmith or weaponsmith, who's at master level, could repair your gear to 65/50 or 90/50. It'd work wonders for people who constantly have to spend a lot of money for full repairs.
I think, if SE plans to add more Deep Dungeons, they could implement one that gives you a "madness" meter that slowly fills over the course of time. The more full your madness meter gets, the more likely your character starts to hallucinate. You'd actually see crazy stuff on your screen, and eventually would become unable to discern reality from fiction.
EDIT: Maybe a madness-inducing Deep Dungeon could be called something like "Realm of Mirrors", where you get to meet Ferdiad again. Because I don't think he dies when you kill him at the end of whatever Duty he's in.