The Oklahoma Sooners and OK. State Cowboys, both currently ranked in the top 20 have a combined 14 kids on their rosters under 6'ft while the other 53 are above 6ft. Of the 14, 4 are middle infielders, 3 are outfielders, 2 catchers and the rest pitch.
If 80% of their rosters are comprised of kids 6'ft or taller, I think the evidence shows that at least bigger ballplayers are being given the opportunity to play at that level. If all skill sets are the same, schools are going with the bigger kid.
Fortunately guys like Rollins and Pedroia told guys like myself, armed with the size matters data, to stick it and went out and won the league MVP award. If your small and can play, go play but just know that you are probably going to have to continually prove the naysayers wrong at every stop along the way......just like every ballplayer that has ever played.