The RTE, everyone knows it's a big disaster. I'd use stronger language, but I don't want this to be taboo.
New social features? These have to place in a wiki. I can see forums, as you need a place to organize talk pages. Not blogs. A wiki is not your personal stomping ground, in line with wiki topic or not. If you want a blog, get a real one like a WordPress one. You can customize, and be limited to the mind, (or software) not the service. Why do we need these anyways? Wikis are not a place to personal or over-social, it's a place to collaborate simply and edit.
I'm losing faith in you Wikia developers. The category editor was good, but you bundled it with the RTE. Mistake. If a good feature requires a really crappy feature, the good feature dies.
This will be my first and last post here.