Personally, I'd like to see buffs to vanilla mobs to make them a bit less of a joke, and new balanced combat mechanics. Also, that glitch where mobs reset their AI after being hit needs to go. I wouldn't be overly interested in new weapons, but if they had unique uses I'd be fine with it. But, singleplayer needs some buffing too if new weapons are added. What I don't want to see is a ton of weapon reskins and inherent decreased difficulty in singleplayer.