Yeah, I think that MetaWiki is overly complicated and heavily lacking in ease of use.
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.
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?