I hope stealth gets a major rework, at least. Or maybe not stealth itself but how the AI handles interacting with it. No NPC should ever guess that it was just the wind when there's an arrow sticking out of them or their colleague is lying dead in plain view (or even just doesn't respond when they call to them).

They should use strategies and tactics that work against stealth. Patrols (including their own stealth patrols sometimes), roll calls, better lighting, positioning of guards to cut off entrance points, traps (and not just the dungeon traps, but NPCs setting new traps when they suspect stealth, where the trap could be as simple as a trip wire attached to metal rings that will jingle if someone disturbs them), spells that locate nearby people, using senses other than sight and hearing, dark vision. Sometimes stealth missions should be forced to end and come back later because the residents realize someone is trying to sneak around and kill or rob them and go on high alert with effective tools to negate stealth. Just sometimes, sometimes it should work like it does in Skyrim where a guard just doesn't want to deal with whatever is shooting arrows at him and maybe just yells threats instead of using a stealth counter (just get rid of that memory of a goldfish thing).

I mean, stealth is fun, but it's not as fun when every single character I make ends up becoming some kind of a stealth archer because the NPCs are effective at generating opposition to everything but that.