When a Di Lacrosse coach says they prefer multisport athletes, what they really mean, I believe, is that multisport athletes have more room to grown, skill-wise, when they get to college, where they will receive the best coaching in the world, be competing against the best, and focusing on the sport year round. D1 coaches have to choose amongst many dominant HS players. The HS player who plays only lacrosse year round has probably peaked (or nearly so) skill wise. The player who only plays in the spring and summer, while playing soccer in the fall and bball in the winter, will get better in college. If they are both dominating in HS, the D1 coach will prefer the later kid.
I have a family member who was a D1 basketball coach his whole life. He said recruiting is simply about getting the best athletes. Once on campus, the coaches will coach them up. Lacrosse, I am sure, is no different. | 
