Darth Vader (after getting well-done barbequed) would have gotten his ass kicked by all the major Jedi characters in episodes 1-3. One of the key points with Anakin is that he's not nearly the Force wielder he was before getting all fucked up. This is one of the major reasons why the Emperor wanted Luke to replace his father as his apprentice.
As far as the acting goes; I don't really blame the actors themselves. The cast, for the most part, is fairly talented; but they have shit dialogue to work with. Lucas is notorious for being a bad dialogue writer and isn't very good with directing actors.