Perception is your ability to notice details.
Think of Sherlock Holmes - he could make deductions about people not because he was smart (though he was), but because he noticed details. He noticed the way they walked, whether their clothes were wrinkled or ironed, if they were trying to hide an accent, etc.

Plus, Intelligence already gives you access to 5 out of the 8 combat skills. It doesn't need to be any more useful.