The Emperor could control it very well, it just requires a lot of concentration. It wasn't his fault that he lost control of it, Luke and Lea(can't spell today :angry: ) distracted him. The Emperor had sucessfuly used it at other times.
As for it being a force power, I haven't heard of anyone else using it and it is a little to big of a power (meant to be used against fleets and the like) to include in a game like KOTOR.
But it would be neat to have a mini force storm that threw enemies and objects around and tore them up. Maybe it would take two rounds to cast and would be broken off if the character took too much damage.