The problem with college teams is that a lot of them don't play enough games for the players to really develop, and, paradoically, a lot of the better teams used to, and may still, ruin good starting pitchers by overpitching them. It wasn't all that long ago that top pitchers would pitch some huge percentage of a team's games, and it may still happen. Ben McDonald, for eample, was a guy who could have been a real major league stud, but his college coach (LSU? Teas?) way overused him, and he was damaged goods when the Orioles signed him, and was often hurt in the majors. Clemens actually went through the same thing at Teas, and ironically, it was thought that he wouldn't have a long major league career because of it. The Red So had to kind of baby him for a few seasons until he got over it.
An interesting fact: Danny Goodwin, a catcher, was drafted #1 at the end of high school, went to college, and was drafted #1 coming out of college. After all that, he played 252 major league games with a .236 average.