The wiki needs category support. Having used wikis for years for internal documentation of operations, business processes, and facts, I've come to find that the typical flat structure makes organizing information into an hierarchical format very difficult. You effectively have to hand-build a Table of Contents or rely on searching/browsing the contents. Keywords are helpful but do not provide a structure to the information which is vital for newcomers.

Adding category support would not take away any of the current features and would help content developers who are trying to organize the information into useable knowledge.