Despite having gone on Soarin' probably close to 100 times over the past 8 years, I never noticed until this last trip in July just how HIGH up you are when you're on the top row! I only noticed because my DS5 was trying to lean forward to look down and my husband panicked and instinctively yelled at him to sit back (it really frightened my husband - now he insists that my DS5, who is our youngest, sits next to HIM on that ride so he can keep hold of him). The thought really scared me after it was all said and done, because I'd never even given a second thought to the possibility that one of my children could actually fall from the seats (the harnesses are so flimsy, they seem useless, so I think I always subconsciously perceived that to mean that there really wasn't any possible danger).
As far as INDY goes, I don't ever remember the height requirement being less than 46", personally. My oldest daughter, who is now 18, had to wait until she was 46" to ride it, more than a decade ago. Also, I have personally NEVER seen them load a smaller kid on the outside of the jeep...they are always seated on an inside seat. As far as I've personally seen, anyway.
IJ is too intense for *most* kids who aren't yet 46", anyway.