When I first heard about the PT I was stoked over the idea that we would not only get to see a time when dozens of totally bad-ass Jedis kept the peace and order, but we would learn more about the origins of the Sith. Unfortunately Lucas dissed me on both counts. The PT never shows the Jedi kicking serious ass, although in most of TPM the Jedi get punked, and a young brat accidentally does what the Jedia couldn't do for the whole movie; AOTC is even worse, since it shows us that Obi-Wan's character from ANH is actually a bit dumb (needs the younglings to explain the obvious to him about a missing star system and cheerfully strolls into ambushes) and not much of a Jedi (gets his ass beat by non-jedi like Jango Fett, lets a non-jedi assassin give him the slip, and on and on). The worst of AOTC for me was that Yoda turned out to be weak in the force, when he couldn't apprehend a two-bit villan like Dooku. In fact Yoda never learns anything of substance from his meditations with the force until ROTS, and then we learn of his communion with Qui-Gon only in passing! The overall effect of the PT was to diminish the stature of the Jedia. We are told that the Jedia kept peace and order for over a thousand years in the old republic, but as it is with too many characters and plotlines in the PT, Lucas never shows us that the Jedia are bad motherfuckers; he simply makes them into the "good guys" having equal fights with the bad guys.
I'm not saying that the Jedia should have kicked ass through the entire PT, since that would obviously be inconsistent with what we know happened. But it would have helped build character, and created more audience sympathy for the Jedi, if in Episode I we were shown what the Jedi were like at the peak of their powers. If Lucas can do this with an Episode 0, he could immensely improve the entire Star Wars saga.