Been thinking about this and have decided that the best attraction in IofA is the If I Ran the Zoo play area for the little kids. In a park full of rides with height restrictions and stuff this is where we spent the greatest part of our time. Truly brilliant play area. And I have to say the Barney indoor play area in Universal is awesome too - Steven and Harry had to be forcibly removed at park closing.
Seriously, Disney could learn a lot about pre-schoolers entertainment by checking out what Universal have on offer.