I've said it before and I still believe that George Lucas is a man obsessed with ideas. A certain concept will grab his attention for a moment, he'll love it, try to use it, and then, once he's bored with it, move onto another idea. These fascinating ideas are what made Star Wars so great (and they easily comprise the most promising aspects of the prequels as well). While I'd say that this is his greatest artistic strength, it also causes him to ignore a lot of other things like continuity, plausibility, and finesse, as well as a whole ton of various emotional concerns (such as energetic dialogue). For instance, George knows what character drama looks like from the outside, and can have everything sitting in the right place, but he doesn't know how to connect all of that to the emotions sitting inside. Or, in the reverse case, when George starts with an emotional motivation (like the fear of loss), he doesn't know how to truly connect that to logical events nor on-screen performances. To do so would require too much work and he wants to move onto his next, fascinating idea.

After that, I think he allowed a concern for money to motivate his artistic choices too much. But, that's not too uncommon. :\

Originally posted by: zombie84
So thats why we ended up with Episode I, a film which shows how an unchequed Lucas goes off the deep end, getting obsessed with aliens and special effects and kooky weirdness and totally forgetting about characters and completely ignorant to constructing drama or a finely crafted plot.

Since I could ignore Jar Jar to a degree (and even found his antics humorous at a few points) I still say that Episode I is the best of the prequels for exactly everything you just described right there. It's certainly not a great film (it's even way below RotJ in my mind), but if we simply expect it to be nothing more than it is (and forget the other Star Wars movies, for instance) it totally works as a fun, fast film. Essentially, Phantom Menace had a ton of amusing crap squeezed into it. While I would never recommend it to anyone looking for a serious, adult-movie experience, it's still a movie you can vegetate in front of (for a while).

If you go to watch the other two prequels for what they are, however, they're absolutely terrible and almost completely rely on their connection to the OT to even seem good. They're both just big, long jokes assembled and dressed up in ways to make you think you're watching something well crafted (while it's actually falling apart at the seams).