ESB is over-rated, IMO. It's just a space adventure movie. It doesn't have the same charm and freshness that Star Wars did.
So in your view, what are the problems which so plague Tron Legacy? I tried to watch Transformers: Dark Side of the Moon last night. Couldn't make it past the Buzz Aldrin scene, too damn embarrassingly bad. Now there's a film with problems, again, IMO.
I think as a sequel Empire Strikes Back is as strong if not better than the original depending on your point of view. Plus the surprise reveal. Few sequels reach this level.
Hey, don't get me wrong, I love Tron! The first one will always hold a dear and special place in my heart. It may go down in history for it's visuals, but classic literature it ain't.