[blerud]

I can't speak for UT, but for Quake, other aspects of the game, such as movement and item/map control have a very big, if not bigger impact on performance than aim. Players with good movement and map control can often outperform players who have godlike aim.

Higher TTK ensures that players with good movement and map control can have the stack and weapons required to out-live and out-damage better aimers in a fight.