1 Wikis are great tools for collaborative content of all types, but the choice for website creators who want a level of collaboration seem to have to choose between a static website, a wiki that anyone (or all members) can edit, or an overkill customized web app.
3 A simple innovation that needs to propagate through wiki software is adding the ability to suggest edits and accept those edits. Perhaps you want a wiki that anyone can suggest and edit, but only registered users can edit freely or accept edits. Or you want anyone, including members, to only be able to suggest edits, and only have moderators able to approve edits and edit freely. Etc, etc.