I agree with a lot of your points. The prequels have some good actors but not a lot of good acting. I blame the script. Hayden was definitely better in Revenge of the Sith and his portrayal of Anakin in Attack of the Clones still goes down as one of the worst things about the prequels. Again, I can't fault him entirely for this because in other movies he is not as big a douchebag (though he's not a great actor) and Lucas either signed off on or, worse, encouraged that godawful accent and spoiled brat behavior that dominated half that movie.

Of the three prequels, I liked Attack of the Clones the best if only for the reason that I thought the clone plot was intriguing. It definitely could have been on par with the earlier films if Anakin was handled better and the love story wasn't so contrived. Two things that I feel would have been easy to do in the framework of the film.

The thing you have to remember about watching A New Hope is that none of the other five movies were even conceived at the time of that movie's filming. It's the one with the most plot holes simply for that reason, and, being the oldest, it's also the most dated effects-wise. However, it's still a great adventure.