I don't really have a point of reference with old DRK since I am new to the game, but the one thing I would love to get reworked is Delirium, it's so... Boring and forgetful, spamming Bloodspiller/Quietus doesn't feel good at all.

Another thing that I would love to see is that animation where your character kinda puts their shoulder against the target and casts this huge blast with their hand return, it's such a cool animation which I assume is from a removed ability.