Well if you have an archer type character, perception is almost as important as dexterity since without it you'll get enormous accuracy penalties unless the enemy is very close.
Perception is also important for determining how many AP you regain each turn out of your potential max at start of combat.
Oh... and, for the very thing you complained about.. spotting traps. Don't want to step on traps? Invest in some perception. If not, just accept you'll be casting heal / using healing items more often.
