Truth be told, I didn't know I was supposed to hate the Ewoks as being "too cute" until the Internet told me so a few years ago.
I was 9...I flipping LOVED the Ewoks...still don't hate em...but I see the point. That said, The best part of ROTJ is watching Ewoks take out AT-ST walkers. 
Agreed.. I can't say I LOVED them, but I enjoyed the movie back then. I might have even choked up a little when the one ewok didn't get back up.. It's really only in retrospect that I dislike them. The original idea to be Wookies on Kashyyyk would have been cooler, but what the heck, it is what it is. I haven't watched the remade version with the new Anakin at the end, I still have it on VHS in it's original format as well as after the first remake.
On the other hand, the prequels sucked. I could forgive just about all of it except two things: horrible dialogue (almost unbearable to watch) and a complete departure from the "Official Lucasfilm Authorized" story line that was quite good. I can understand minor deviations, but deciding to completely rewrite everything that has been published just because of his massive ego, even when his ideas were so clearly inferior.. that is what killed it for me.
You could say just two factors isn't too bad, but I enjoy movies for 3 reasons:
1) special effects. Come on, it isn't the story that made Star Wars what it is today. Back then the only way to see what Lucas' team did was to read a book and have a good dream about it. Today, not so much, but I still see movies as much for the sights and sounds as for the story or anything else.
2) The story. When it comes to sequels, it's all about bringing the elements back around to complete the story.
3) The acting and dialogue. Face it, even a crappy subject can be great when the actor is good, the dialogue is engaging, and the director can put it together in a way that makes you FEEL.
You can have any one of them be crap if the others are good and still have a decent movie (or even a record breaker). But when 2 out of 3 are complete crap, not even as good as a B movie at 2 am, even the best special effects in the world can't really make it worthwhile. I saw Star Wars twice a week for two months when it came out in the theaters (had summer movie tickets and snuck in to Star Wars every time). I saw the prequels once in the theater each. I tried to watch each a second time at home, just couldn't make it through them without getting irritated at the awkward dialogue and terrible acting or at least falling asleep. They just don't have too much in the way of redeeming factors.