I have just been revisiting the PT because I decided return to tackling them before trying TESB, ROTJ, or TFA. After watching them again I have to agree that ROTS is the most dramatic and is a great fast paced action film and tragedy. But I still feel that TPM got the universe right. Yes, we see the galaxy looking pretty good, but like fruit that is about to spoil, it looks good on the outside while hiding the rot on the inside. And the story goes where the characters are. The focus in the fall of the Republic so spending so much time on Coruscant makes sense.
I think one would argue though that the focus should not have been on the fall of the Republic, that should have merely been the backdrop to Anakin’s story. It isn’t quite in keeping with the other SW films to have galactic politics so far at the forefront of the story.
It was certainly a risky thing to do, but the change in themes/style is actually one of the things that I admire the most of the PT. I kind of wish that each trilogy would be as thematically and stylistically different as the PT was compared to the OT. I think it would have been much more interesting, but of course that would have created a plethora of problems from a commercial standpoint. But I do admire Lucas for doing something different.
However I completely agree with yotsuya that the PT doesn’t work as the first films in a series (for several reasons), but works fine as a follow-up story or spin-off.