jemaz,
I guess you have to take it on a case by case basis. The little curve baller that I threw for an inning every one of our 5 all star games is the smallest kid on the team and has very short parents. He's not likely to pitch even in HS.
We also have two taller kids with fairly tall parents who throw reasonably hard and could eventually do well as HS pitchers. Both of them are throwing curve balls. One hasn't had any problems. The other learned to rely on the curve and his fastball didn't develop much at all this year. My son projects to end up about 6' so he may not pitch after HS unless he eventually develops a very good breaking pitch to go along with the change and fastball but he's very effective for now without the curve and his fastball continues to develop.
Even if a kid doesn't pitch a strong arm is a plus in baseball.