While I know this is great for high school (JV at least), what about college? For professional ball? If I threw a 2seam/sinker, cutter and change, would I need another offspeed?
To me establishing a good change is essential. It is one of those pitches that if mastered it’s almost unhittable, even if the hitter knows it’s coming. I teach a change up way before a breaking ball. So yes is the answer for me.
It’s good to have a change up as your off speed, you don’t necessarily need a giant curve or a knuckle ball. That being said, if you are a guy who goes many innings in a row it might be a good idea to add a slider or a curve, but that pitch should just be an extra unexpected thing to go to. Spend most of your time working on three solid pitches, with the other just being a bonus.