If the little league was making millions of dollars from the kids likeness, then yeah, they should at least see some of that.
I don't see a problem in at least letting players make money on the free market. If somebody wants to pay you for an autograph, your jersey, or your time, what's unethical about that? And yeah, the average role player gets a good deal with free school, but the best players get undeniably screwed while they're in college. If a student on an english scholarship writes the next Harry Potter does the school deserve all of the profits?