Daxx's Wife here. DS8 loved this show (I hesitate to call it a ride). He is a huuuge Stitch fan and thought this was great! I have to say that I enjoyed it as well, inc. the ewwww factors!
However, I can understand how some children would find it intense. I think of my Kindergarten students who might be afraid of the dark setting, the sense of not knowing what will happen next (esp. being in the dark) and the fear of what might happen to them in the dark. I would def. say this is not for the kids who are afraid of things that go bump in the night.
I want to add that, even as an adult, I cannot stand the restraints and seats. Both, in my opinion, are very uncomfortable. The restraints came down heavy on my shoulders and were pressing on them. I know they do this so I can't get out of my seat ... but still. Yeowch!
Does it have any alien still in it? Yes -- the part where the room goes to pitch and they're flashing lights around as if looking for Stitch. That was the only similar thing. Nothing horrible ... smell effect, sound effects, Stitch bounces on your shoulders and blows in your ear and water splash and that is about it. Oh, and the cyborg thing that you have the pre-show with isn't as menacing as he used to be ... they've added a hat and other things to "warm" him up a bit. And, the cute little alien (whatshisname?) - the yellow fuzzy one, he's still in it in the pre-show segment.