I was having the same results and I decided to start calling my own plays and found the run game to be much better for the CPU.
6 games doing coach suggestions: 70 rypg 3.2 rypc. 245 pypg
7 games calling my own plays: 126 rypg 4.1 rypc. 245 pypg.
I still call a lot of the same plays as in coach suggestion but I have found it more of a challenge to call my own plays on defense and offense.