I think a 2 year rule would help both the college and NBA game. It would spread out the talent to other teams. Teams like Duke/Kansas/UK reload every year. Well just think this year's crops most likely would go to other schools because they don't want to be sitting behind the Parker, Randle, Embiid. Sure some kids still want to go to the big programs but I think the talent would be more spread out. It helps the nba because kids are better prepared and more mature (hopefully) with two years under their belt. As it was mentioned before, it also gives the NBA a better chance to evaluate a kid.
Personally, I just wish they would make it at least to their junior year. I know we can't stop people from wanting to earn a living. I think that if a kid doesn't want to go to school at all then he should be able to enter the league.