don't know how much i can help out with your question as i have been going yearly the last 15 years.
as much as i think i know the parks, i can't remember when everything started.
lets see.......fear factor is new, mummy, shrek, jimmy neutron....think they all came in the last 2 years.....
the beetlejuice review since last year has new songs, well, not new but different songs......
this is on the universal side.
if there have been new shows/attractions at ioa in the past 2 years, i am drawing a blank on them right now.
i'd have to get out my old park guides to see what rides/attractions started in what year.