Unfortunately, we were taught from our start that coaching doesn't affect the game except which plays you have available. I've always put my 100% attention to play knowledge and strategies.
If they did matter JDB would need to re-think the system. As it's currently constituted the positional spots can only be filled by sub-70 type pick ups, basically.
That would drastically shift the game if the coaching ratings in pass catching per se saw an affect to your WRs ability to catch the ball on an FL Hitch and go.
Poor rating = WR runs an improper route the ball sails harmlessly to the ground.