Damn, it was announced Summer of 2011! Never thought SSB U/3DS would have such a long development. Carpal Tunnel is a bitch
They hadn't even started the game when it was announced so it really hasn't been that long.
Pretty weak excuse really. At this point he needs to get someone else to do the balance testing. It's not like the games are even remotely balanced anyway.
This style of game requires a lot of balancing because if you add a new character or tweak moves you will have to tweak most if not all of the cast as well to keep the game balanced.