I understand your points and concerns, plague. I just think that implementing this rule would probably have unintended consequences that are worse than the current perceived problems. I think 3 immediate things would happen if you punished taking walkons by stripping away recruiting cash for the following season:
1. There would be fewer competitive battles among equals. If you're going to face punishment for losing a battle, that is going to discourage battling, unless you know for certain you can win.
2. Predatory type battles will increase. You'll see even more A prestige teams jumping on B prestige teams and on down the line as teams clamor to fill their spots with serviceable players to avoid the walk-on penalties.
3. One of the best ways for mid-majors or rebuilding major programs to build themselves up is to take a couple walk-ons and maximize their dollars per recruit. That strategy pretty much goes away with this rule change. I think I understand that to be your intent here, but I actually think it hurts the middling programs more than the elite ones. The elite ones have the prestige and conference bonus money to compete and bounce back no matter what. The middling teams don't, and need a way to get on more even footing, and that will have been all but eliminated.
In total, I think this proposed rule would be likely to hurt overall competition.