This is a fun experiment; but if you want my 2 cents, I can't help but feel roster composition, and class distribution, is holding it back.
I get it's a no QB/WR/TE offense, but 16 RBs is a bit excessive. If you recruit 2 a year, redshirting one, you'd have a RS SR, SR, and RS JR to start every year. You could then recruit 3 OL a year, RS one, and then start a RS SR, 2 SR, RS JR, and 2 JRs (or 1 RS SO) at the 5 OL and TE spot. You can easily run this offense, with nothing but upper classmen starting, recruiting just 5 offensive players per year (TBH, you could probably get away with even 4 every other year) freeing up the rest of your class for defense. The biggest benefit this experiment offers you is there are 3 positions you can entirely ignore on your roster, but you don't really take advantage of that by adding so many additional RBs and/or OL.
I realize this would take some time and creativity to adjust, but I also think a more evenly distributed FR-SR class would allow you to take more advantage of this potential roster composition instead of having one giant class (22), one medium (12) and two small ones (7, 6) particularly when the largest classes are back to back.
I just feel like you're sacrificing something very significant (throwing the ball) attempting this experiment, while not truly maximizing what you're getting in return (extra roster space for your defense by not using QB/WR/TEs).
Regardless, I am enjoying following the process