I was talking to a friend who played some pro ball last night. When he was playing JC ball he went out and was throwing well in front of scouts, getting people out. No interest. His coach told him that the next time he threw in front of scouts he'd better throw harder so he did. He didn't pitch as well but he got interest and eventually was signed.
Back then we were told if you couldn't throw 85 don't even bother. Nowadays it is the same although with the new guns that 85 mph fastball would read 88.
You've got to be able to pitch or you won't help your team and won't be a pitcher. Eventually if your goal is to stay in baseball you'll also have to be able to throw hard enough to generate interest. Once you're signed they'll tell you to how to pitch and only results will matter.