Wait...or I got it wrong or your post is a little misleading, you haven't played ONLY Little Big Planet, are you? Because LBP is a great creative tool, but as platform is almost abysmal, and platform is my favourite genre.
However, I agree with the first part of what Rol says...using your (the OP) logic, GTA it's better than any game since you have car driving, you have shooting, you have fighting...but what a game like this lacks is depht in any department. I mean, you can't compare GTA driving to GT5 driving, you can't compare GTA shooting, to Killzone shooting and you can't compare GTA fighting to Tekken fighting. The same logic applies to platforming. You may don't like the genre but it doesn't mean that the so-called platforming you get in sandbox games is better than the real deal.
As for what I like about platforming, as the others have already said I ilke the learning curve, the ability to imporve your skills just for the fun of it. Of course a platform needs a great control scheme and a great level design to let you do that.
