I do realize there would be less quality players in CFB. But not as many as people here seem to believe.
A total of 224 players go through the NFL Draft each year. So let's use that number for this hypothetical minor league. I doubt there would be that many as this league would most likely max out at 16 teams or so, but just for a starting point.
So this league is going to draft anyone from High School seniors to college seniors. The majority of draft picks would be college sophomores and seniors/juniors who just missed getting picked. You'll have a few get drafted straight out of high school, but I would bet no more than 10-15 on average.
Not even everyone who is good enough would bypass college. Peyton, Eric Berry, Andrew Luck, etc all would have picked playing college. Hell, we had 3 guys good enough to get drafted who decided to come back and ball with us this year. A minor league wouldn't have effected them.
I believe a minor league would relieve 2 issues. Paying college players and getting rid of the guys who want to major in football. Most of these guys want a degree. But the football major guys end up being the trouble makers. They have to be babysat.
This is a college first and foremost. If kids aren't coming for an education, they dont need to be there.