I see this much like the NBA D league, once you get to 22 or 23, there are very few players who will later make an impact that are worth keeping on contract to spend a few years in a minor league. Especially in football, where there are too many chances to get hurt before you even sniff the NFL.
Football seems like a sport where you are either ready to contribute enough to go ahead and play or you are not. Obviously there is room for improvement for a lot of players, but most of that is actually being in the league and getting used to the speed of the NFL. I just don't see how minor league really does much to produce enough players to make it viable.
Although, this could be a good venue for kids to improve their post play antics. After watching this past weekends games, I've just about had it with the NFL. I'm tired of having to watch some kind of move or dance after every single play. Hell, NY was getting their asses kicked by GB, guy makes a basic tackle and has to get up and show the world his dance moves. You're getting your ass kicked, what are you celebrating?
OK, old man rant over.