I will def agree with the CPU run block being a little over powered. In every game I also have to put 8 in the box to have a chance at stopping the run. I just played Green Bay using the Seachicks and I was finding it difficult to stop their backs no matter who had the rock.
The thing that I notice most about it was that they would not really pass unless I got them into 3rd and long and that's not really their style. I don't think it is a play book issue as much as a the run is overpowering issue. I am looking for great backs to be tough to stop all day, not the Green Bay backs. Just my 2 cents.