I'm a big fan of ModTer because it fits the aesthetic of Blockland much more than standard Terrain. If only there was a mission editor-esque program that works with ModTer.
As far as updates, it would be cool to see more default gamemodes, events, tools, etc. Maybe default server previews, IRC, and an in-game friend list.
Anything that makes community interaction easier in-game would be cool. I always used to think RTB should be a default feature. Tired of seeing knock-offs that conflict with eachother. Finding the addons you want is a hassle nowadays, it sucks.