A note on number of pitches - if Sale is to ever make the jump to 250 inning super stud ace, he's going to need more than three pitches. A couple of times through a rotation without your best stuff is fine for a guy with 2-3 really good pitches. But if one's not working for you, or it's late in a game and you're tired, the more items in your repertoire, the better.
On pitches from different slots - you'd have to think if Sale ends up tearing a ligament in his elbow, step one of his rehabilitation is going to be learning an arm slot that won't end his career. So I wouldn't take learning any pitch off the table.