[AtlUmpSteve]

Walking doesn't need to mean you keep walking through the pitch. Personally, I use a "one step set", which, when timed properly, gives you a step from one foot forward to square with home plate when the pitcher starts her motion, you are set when the pitcher begins her step and whatever she does with her pivot foot, and on the balls of your feet ready to move in either direction when the pitch reaches the plate.

This accomplishes every agenda. You are not stagnant and locked at the time you need to be ready to move, you are ready to drive off in either direction if the ball is hit right at you, yet you are still (momentarily) at the decision moment relative to the pitcher's step/slide/leap (whatever), to judge the legal/illegal pitch.