George Lucas had how long to work on the prequels, to correct plot holes, bring in other writers to add to his ideas ... or come up with new ones, work on dialouge and interaction. I don't know, sometimes I just feel like the effort wasn't all there to really bang out the best possible story/screenplay. Especially if only George Lucas was working on the meat and potatoes of it all, which I believe is story. Two heads is better than one, and then some, by throwing out ideas and keeping/eliminating the things that do and don't work.
Call me crazy ... or naive, because I'm not in the know when it comes how things work in the film industry. But when did Lucas actually start to really work on the screenplay and story side of his prequels? A year or two before the release of PT (I seriously don't know)?
*edit*
By the way, what did you use to take that screenshot? I only use PowerDVD, but it doesn't look as clear, or as sharp.