Hmm, the crying, the whimpering, and the grabbing of ass wasn't a clue for that pair at all. The reason it doesn't seem right is because they actually mention, OUT LOUD, that they are basically brothers and sister. That and Ventus is just too innocent, and Aqua too mature, and terra too wild.
Okay what I have to say about this is. Aqua/Ven doesn't work cause Aqua like takes care of Ventus all the time. Aqua/Terra would make more sense but i don't like that either. I mean they're practically family and it wouldn't make sense for any of them to go out with each other.