There seems to be a bit of interest in this, so here goes. If I was able to get my GBA Action Replay to work, who would be interested in me Pokebanking some "999 stat" Pokemon into X and Y? I managed to get my friend's 999 stat Jirachi in a few nights ago, so maybe it'll work again.

Basically these Pokemon would be unbeatable as they are completely maxed out.