Well, I don't hate PT, but I think it is a bit weaker compare to OT for the following reasons:
3. Episode 1 definitely got "kiddie-ized" too much with the whole Jar Jar thing. Frankly there is a version out there that cuts out many unnecessary parts of Jar Jar and the movie runs much smoother. THough in Ep2 & 3 GL kinda learn and cut short such sessions. A few funny part is great, but Jar Jar is trying too hard. He can be both funny and serious as portrayed in the novels and what not. Also I think that is how PT starts off with a bad leg for some.
2. Trying to include too much cool stuff. Yes, this is especially true to Ep2 where they deliberately include elements just to awe audience (and esp fans) The huge jedi arena battle, Jango Fett specials and what not, deliberate overplay of yoda's sentence structure... overplaying the crowd pleasing elements overshadowing the story.
1. GL HIMSELF. Well, GL is GREAT when it comes to cool special effects and ideas, and I do mean great and wonderful. That having said, he does need some help on his script writing, and HIS ABILITY TO WRITE DIALOGUES ARE SHIIITTTTTY AT BEST. In OT, where is is not that mega movie overlord he is today, people give him suggestions to his scripts and what not, and he is good with suggestions. But nowadays, enough people would just be yessman to his ideas, hence the inferior result. Also, in OT the good actors help make the dialogues more reasonable, many cool lines in OT are from the actors themselves. (think of ""I love you" "I know" vs the cheesy love scenes in PT that makes me wonder if GL got his wife by the caveman way with a huge club whack on her head)