With NaNo coming up in a couple months and the editing phase that follows, I think it would be useful to have a friends/contact list of users you collaborate with for easy sharing.
Maybe I should put a different line feature request, but I'd like to see a few different _kinds_ of collaboration, one of which is 'owner/editor'.
This would represent a group of people (who I, as a creator, decide I trust) who may generate/maintain a baseline set of templates, world data, whatnot. So, I, as a creator, could base my world on a common world controlled by editors I trust. I could change things without jacking up the original data. Basically, I think this might devolve into 'change management' of some kind.