Actually, short hop uairing with a is better than c stick in some scenarios. It comes out ALOT faster than the c stick. Watch shroomed play, all those uair approaches he does are uaired with a (unless hes just insanely fast at moving his fingers to the c stick).
Also, you dont have to touch lightly, if you hit jump (x/y) theres a jumping animation in which you can mash up on the control stick and it wont make u double jump. Then just hit A from there and u got a short hop uair! then course u gotta fast fall and stuff. no l cancel required though since animation ends before u hit the ground.