Maybe someone could treat Wikipedia as a back-end and implement a cleaner, simpler, and more powerful UI on top without having to fork the entire database?

Between the various gadgets there, I'm sure you can find what you want. And you can write your own too. There are a variety of user-contributed stylesheets and scripts listed elsewhere on the site.

Unless you're trying to do admin tasks, I'm not sure what you mean ease of use. Just click the edit button and start typing. If the formatting is wrong, someone will clean up after you.

well, you did say obvious vandalism. anything other than nonsense could be a trial by fire to "correct".

there was a satire making the reddit rounds (and presumably hn?) a few months back in which editing wikipedia was extrapolated to time traveling, complete with inane policy discussions.

found it: http://www.abyssandapex.com/200710-wikihistory.html