Aliens
The Empire Strikes Back
The Two Towers
Gremlins 2
The Wrath of Kahn
I guess I could agree with those... But I can think of ALOT more sequels that were much, mcuh worse than the originals!!
Austin Powers
Highlander
Sister Act
Three Men and a Baby
Look whos talking
Batman...
I could go on forever... true some of these movies weren't very good to begin with, but the sequels were utterly apalling...
If they made a sequel trilogy, it would be done for the sake of it, not because anyone had a great idea. Most films where they decide to make a sequel, and then try to think of ideas, rather than the other way round, tend to be pretty awful...