Shrek, Jimmy, and Mummy will be new to you. (Hitchcock, Hanna-Barbera and Kong closed)
I don't remember when it happened, but Posiedon's Fury was changed entirely to include a new storyline. If you saw the original, don't bother with the new version. It basically sucks.
Dudley got a smoother drop, but the angle didn't change. It can't, considering it goes through a shack at the bottom. Some people seem to think it's more intense anyway now. I think they're dillusional.

I hear some of the effects were fixed, like the train light. Don't know if they were working when you went or not.
Jurassic Park got a new restraint. There's also a new effect that hadn't been working previously, but I'll let you find that one yourself. You'll get wet.
The make-up show was updated to include props & scenes from Van Helsing. They also updated the gag at the end of the show.
They updated the Earthquake pre-show.
The Triceratops Discovery Trail was permanently closed.
I think that's it. All the other rides are the same.