I teach a sideways finish. Just from my personal experience, I can get pitchers to throw significantly fast with this type of finish. Which has also had many parents worried that they will not be ready to play defense and protect themselves. Hitting your spots and having speed is a good way to prevent batters from hitting the ball back at you. Not that it is impossible but if you stay off the middle of the plate, the hits usually stay out of the middle of the field. If you are turning or moving your plant foot while you are trying to release the ball, you will miss your spots and you will throw more pitches down the middle. You should keep your landing foot planted through the release to keep your motion going to your target.
Sounds pretty easy but here is the trick, you have to be done moving before the catcher catches the ball. If you are still pitching as the batter is making contact, there is a great chance you will not be balanced and in control of your body to react. Being done with the motion, under control of your body, and focused on what the batter is about to do will take precious split seconds off of your reaction time that you need not only to protect yourself but to also field your position.
So, do not add a defensive stance to the end of your pitching motion. It will effect your speed and control causing you to give up more hits and more potential hits up the middle of the field.