I think everything I didn't like about the Star Trek movies done by JJ (too much focus on action, overly-simplistic story) would make him a solid choice to direct the new Star Wars films.
I also think movie opinions are a subjective thing, and it's difficult to put opinions into words sometimes, so I don't want anyone to feel like they have to defend their opinion of any of the Star Wars movies, but...
The prequels were bad. Like, embarrassingly, terribly bad.
They were. Each one had only a few scenes I liked. Particularly RotS, which while bad, was at least the best of the three.
And some performances were consistently good...(cough) Palpatine (cough)...