From personal experience, I can't speak for anyone else. Per my player settings and playbooks, I haven't noticed any difference. For example, I do have a full run playbook, and I haven't noticed any drop-off, except for "WE" on my receivers. They are not getting enough playing time. Don't worry about that too much; as long as their other attributes are growing, you'll be fine. The same can be said for "LB" if you're not playing them enough, but that will dictate formation. Again, same scenario: "WE" might drop, but as long as other attributes are continuing to grow, etc.
From what I've gathered from the forums and advice from the old-timers. Have your system and recruit to that system to the best of your abilities. It was mentioned to me in another chat that some of these guys have been playing so long, they know who to recruit and what playbook(s) to run against pretty much any formation.