I actually like the Kansas rules which force kids to diversify or to set out. With the exception of a few superior/extraordinary kids, I personally think they need a break from time to time. They are developing and growing all thru thier young lives, and not all at the same pace. Many kids will never be a true star in a sport. But, if they are encouraged to participate in several different ones, they can find one which they excell at.
And by excelling I mean on a personal level as well. One doesn't have to be a champion to achieve success. Sports teaches us much more than that, even tho we only seem to recognize the champions.