Then again very few pitchers actually practice throwing to the corners of the zone.
???
really? why not?
It never occurs to them to throw it as a low pitch.
If you can hit the spot any corner of the zone is fine. If it has good movement, even better.
Movement?
Im not following what you mean here? My definition of a fast ball is just that... no movement.
Changing the release angle of a fastball to hit low zones would be a snap over drop, and tilting the posture back an inch or 2 would result in a high pitch aka fastball.
I'm 100% on board to hitting all 4 corners and everything in between (as long as we're on the edges and not dead red). I'd suggest adding this to your practice routine.