You look in the big leagues and there are all sorts of different mechanics, different ways of getting into a good throwing motion. When pitchers and pitching coaches talk about mechanics, they mean the motion that a pitcher uses to throw the ball on each pitch. Solid mechanics are not only the foundation on which the most successful pitchers are based, they also help decrease the chances of injury. There's a lot of philosophies floating around. It's not going to happen.
Good mechanics can help elevate a pitcher through the minor leagues and into the majors.
That's big-league command, using both sides of the plate with all his pitches. If you can do those three things, you're going to be a major league pitcher. A pitcher's throwing motion can be broken down in any number of ways. The first two are the most important. From Grover Cleveland Alexander to Bob Gibson to Roger Clemens, all great pitchers have had great balance.