I rewatched them all back to back in one day for the first time in ages a couple of weeks ago, and do you know what? I really enjoyed them. It's been easy to hate on these films down the years, but really, I think they're pretty damn good overall. A lot of the visuals are still spectacular and hold up very well today. Problems? Sure. Remove Binks from The Phantom Menace and make Anakin a little older and that film would be much more solid than it is. Darth Maul is a superb, if underused villain. I would still say that it's the weakest of the three, but still has some great moments and the visuals hold up very well for an 18 year old movie.
Attack of the Clones is where the 'all CGI' criticisms come in with most people I suspect, but I bet a lot of people don't actually realise that a hell of a lot of these movies were created using practical effects - the arena in Geonosis, for example was a miniature, and there's tons of other stuff too (check out the big thread on Jedi Council Forums - very informative and interesting with loads of production imagery) the 'all CGI' criticism, is quite frankly, total bollocks. Attack of the Clones really just suffers from the stilted love element and the droid factory sequence with some truly cringeworthy humour, mostly from threepio, but they represent a small portion of the running time, the rest is all very good in my opinion. You've got Boba/Jango Fett, Obi-Wan on a detective style hunt, seeing Yoda fight and use force powers in combat for the first time, Christopher Lee, epic battles, what's not to like?
Revenge of the Sith is a fantastic film, right up there with ANH and ESB for me and arguably has the least problems of the three. Only a couple of bits of poor dialogue and the 'giving up on life' bit spoil the party really. Revenge is an outstanding effort, and is easily the best of the three in terms of entertainment and visual effects. McDairmind owns this movie and is a delight to watch. The fall of the Jedi is a truly heartbreaking, emotional sequence that flows into A New Hope really well. I don't even mind the Vader 'noooo' scene.
Overall I really enjoyed the world building and the art deco influences, especially Coruscant, you can see Lucas was trying to give a roaring 20's feel to it all, paralleling our own world's fall in the 30's and 40's almost. There's issues with the films, but what film doesn't? I'd certainly watch ROTS over TFA, and maybe even the first two over it too. The scores on all three movies are excellent also, far better than the tepid efforts of TFA and easily on a par with the original trilogy. They're worth a re-evaluation I think. They were every bit as groundbreaking in many ways as the original trilogy but just don't seem to get the credit they deserve. I'm not saying they're as good as the original trilogy (bar ROTS), just different. At least they told their own story instead of the lame rehash that TFA was.