I think it is an excellent game. I can't actually find anything wrong aside from maybe one or two individual pieces of level design on the land battles. Everything about the game is to me very impressive. I reckon it is one of the best handheld games of all times and alongside Super Mario 3D Land, Mario Kart 7 and Legend Of Zelda; Ocarina Of Time 3D my fave game on the system.
One thing that I don't understand is why all the fuss about the controls? I find them easy, intuitive, accurate and comfortable. Maybe not the most convenient but still excellent. I've played it for over 2 hours straight without a hint of discomfort or ever once feeling that they were awkward.