I'm guessing you've never used the Shift key, have you? Problem solved.
WASD would force the movement into an orthogonal orientation. You'd only be able to see your character from 8 angles. Plus, moving while attacking would mess up balance and animation in a big way. So no thank you sir.
Q u o t e: Assume that whatever Grug says I agree with, so any loner he's arguing with instantly loses 2 to 1. -Cpslostudent