Why is having a healthy stable of backs a "difficulty" to some people? Depth at RB is one of our biggest strengths. It enables us to keep fresh legs in the game at all times.
As far as who gets the majority of the carries, Payton is going to continue to ride the hot hand, and right now it's Ivory.
2 weeks from now it could be Bush, Thomas, any one of those guys. They're all capable of getting hot. I don't see this as a problem.