I’d say the PS3, since there are already two Final Fantasy’s in development, and there will likely come a third (FF VII remake?), and there will likely come a lot of big-budget RPGs to the PS3.
If for some reason Kingdom Hearts III or a real Dragon Quest comes to the Wii, then the Wii could be the new RPG leader, but except for Fragile and FF. CC there isn’t much special in development.