This basically.
Fix the progression.
Make recuriting more realistic / unpredictable.
Improve rating system and depth chart system.
And other things that have already been mentioned.
Doing stuff like this would an 85 man roster a necessity. Right now it'd just be an unnecessary luxury. It'd look realistic and would be cool to have, but there's no real reason for it. This is a game where you could use the same ~25 players every saturday and not suffer any consequences.