I agree that in retrospect, Episode II would have been a much better way to start off the series than Episode I. However, if done right, I think the idea of starting the story with Anakin as a small boy would have been very interesting. I'm thinking of Godfather II as a correct way for a "prequel" to begin Don Corleone's story from the time when he was a small boy, then showing him grow into a young man.

So I think having all six episodes cover the life of Anakin since he was very young up to his death gives it a more epic story arc, but I don't think it was executed very well. For starters, I would eliminate the "Spy Kids"-like finale in Episode I where cute little Anakin accidentally destroys the command ship and saves the day.

"I'll try spinning! That's a neat trick!" (I hope I never watch that scene while going through a deep depression, or it might send me over the edge.)