For me these sequels actually were better than the first. What and why are any sequels are better to you?
Aliens(2) - More action, more aliens, space marines, good build up.
Scary Movie 2 - More edgy Humor than 1 and 3. Haven't seen 4 though.
Rambo First blood 2 - He goes back to Vietnam which is more interesting to me.
Final Destination 2 - more grit in the gore, and more intense than the third or first.
Star Wars Return of the Jedi - the dialog with Darth Vader and his son have more heart in it because they know they are father and son. And Vader finally turns good, sacrificing himself to save his son.
Indiana Jones - Temple of Doom - I became tired of Nazi shit and this was a fresh change.
What about you?