I agree most of all with the first and last paragraphs of your “Big picture”.
If the premise is that a C grade represents an average B1G program then I see QB as B, RB as B- limited by the OL, WR as a wildcard B limited by QB and receiver experience with routes and timing, FB/TE as B, and the OL as a C or C- improving over the season.
In other words, good coaching and player development over the season will have to happen. I am concerned, but not ready to jump off a bridge.