Certainly, but I believe the only way NBA Live 2004 will be completely slowed down will be if the CPU doesn't play at lightning speed. I'm sure I don't need to go into any more detail than that, we all know how fast Live 2003 is.
As far as your idea goes, it would be further improvement to the rebounding issues that were somewhat fixed with Live 2003 (offensive rebounds more difficult than defensive rebounds, fewer of them), and would better utilise rebounding ratings. Players with higher ratings would have less problems tipping the ball to themselves or their teammates (a la Dennis Rodman), while poorer rebounds would bat the ball to an opponent or out of bounds. Players with better ratings would also have a greater chance of grabbing the ball rather than batting it away - though depending how random that was, it might become annoying.
Nevertheless, I agree it would make rebounding better. I don't think it would slow the game down significantly, but it would be a good feature.