I don't know how complex it would be and how hard it would be to balance created plays with defensive plays or if it would be a challenge at all. However, I do know that it could be useful to add some level of uniqueness to each teams playbooks. Plus if a team has a really good TE for example they can build plays where he is the primary target and scheme ways to get him the ball

https://majorleaguefootball.myfootballnow.com/community/5/2650?page=1#17642

The developer has commented on the idea here in this thread

Oh okay, I just joined a few weeks ago and haven't had a lot of time to scroll through, I'll look back rq tho, thanks.