Even on crossbows, perception is a waste as speed gives more damage when you compare crit given by perception and additional attacks given by speed (even when adjusting range and move to compensate).
In combat, the only thing that's kinda good is to have an even number of perception (if it doesn't cost too much), because you want an odd number of speed.
The perception and light-stepper talent on Wolgraff aren't wasted, because you need at least one character with perception for traps, so if you pick Wolgraff he becomes your cautious explorer. Pay also attention to how much stats he has: he has a non standart amount.
And yeah, crit doesn't matter on (well-built with backstabber) scoundrel.
