I've thought about the idea of having a JUCO, HS or NAIA level. My thought process is a bit different though.
I say you keep the coaching positions open to people who want to try the game out. Essentially, make it free to coach at one of those schools, but greatly limit the playability. Mainly, just a sampler so that people can actually start reading PBP and gain an understanding of the game. Or if someone is on the fence about the game, they can give it a try without paying anything. Likewise, even if those users don't keep up with their teams, since they'll mostly be controlled by the SIM, you don't really have to worry about teams tanking and such. Don't let them have playoffs, create formations, use advanced depth chart...etc.
You can also use the players that are generated in the free division in the game. After each season, give the JUCO/HS/NAIA players the opportunity to transfer to a NCAA school. You could even set it up so that coaches have to convince the player to leave JUCO.
There are definitely more important issues that need to be dealt with first. But I think something like this could really make the game even more interesting, while adding some marketing value.