It's not until later in the game that things start to get complicated, and when they do, the controls can't handle it. The levels get smaller, tighter and more crowded, and your dragon's long, slow turns mean it takes a little while to focus back on a target you've overshot - bad news if you're on a time limit, or if that target is faster than you. You can, in theory, pull a quick 180-degree turn by jerking the controller straight up, but this move is just as likely to do nothing or to send you rocketing straight ahead, getting you even further from where you want to go.
Making matters worse, bumping into walls or other objects sends you bouncing off in some other random direction. Nowhere is this a bigger hassle than when you're fighting "battle beasts," giant four-legged creatures that need to be brought down by flying low, attaching a grappling hook to their legs and flying away to trip them up. (And if that sounds suspiciously like dragging down AT-ATs on Hoth, then you're on the right track. Lord knows we really needed to do that again.) Pulling this off is difficult enough with the motion controls, but if you bump into the creature's legs or sides, you'll carom off in the opposite direction and have to re-orient yourself for another run.
If you're actually locked on to an enemy, meanwhile, bumping into an object will send the camera into a berserk spin around your target, which is disorienting to the point that you can actually lose sight of your own dragon. This can be quickly remedied by letting go of the lock-on button, but then you'll have to turn around and find your target all over again.
