Once a pitcher shows he has draft potential, certain stats are more valuable than others. Sometimes the lack of certain numbers can create negative concerns more than good numbers actually helping. (if that makes any sense)
Some of these stats include those that everyone is mentioning here. Another important stat is GB vs FB outs. A pitcher getting a large % of his outs on ground balls vs fly balls is a big plus in most cases. Ground ball pitchers are in demand, especially if they have average or better MLB velocity. It usually means the pitcher has a good sinking fastball or split finger and a good breaking ball. The sinker is a big pitch in professional baseball these days. Nearly every MLB pitcher you see with an average or below average fastball has a real good sinker.