The prequels, especially TPM & AOTC seem to have been written rather hurridly and without much passion or interest, for having had almost 20 years to think it over and come out with it.
No. You are right about AOTC. They practically shot from the rough draft. The same is true about ROTS. But you are wrong about TPM it was the story that Lucas had spent the longest time writing and revising from the original concept. It's undoubtedly the one story from the prequel trilogy he had invested the most time and energy.