My nearly 7yr old was deathly scared on Dinosaur ride - but he enjoyed the Jurassic Park Ride - He understood that there would be dinosurs and that they were fake - He looked a bit terrified at the sight of the Trex - but was willing to ride JP more than once - so he must have had fun!
He loves Splash MTn, Dudley - etc - the fall part does not scare him (funny, I am just the opposite....)