Things I wouldn't miss

[kazak]

I kind of agree about the dreadmasters. Totally trivial for some classes, yet they just ruin a whole dungeon level for others. And I mean ruin in just a really tedious, un-fun way, not a challenging or exciting way.

[Ploppy]

Items disappearing after you leave the level. I can't remember what the original reasoning for this mechanic was, but in the end it just encourages seeking out spoilers and plotting out an ideal path through the areas to make sure you never accidentally enter a place you can't clean out on your first go.

I'd also prefer very mildly randomized area levels to the current rigid level scaling. I hate thinking "If I push back the Assassin Lord for three more levels I'll start outleveling him" or "If I go to the Dark Crypt now, the timed encounter will be much easier than if I wait until the next level." Basically, anything that can be reliably predicted on every playthrough is bothersome.

[Postman]

Items disappearing after you leave the level. I can't remember what the original reasoning

Reasoning is that not found unique artifacts could appear again in another place