Similar to the unused "leadership" and "experience" etc. of STHS, the mental aspect of the game is very important. One easier way to incorporate this aspect into the simulated game would be to add a "Locker Room Guy" attribute. The LRG attribute would give a small boost to the player's linemates. Everyone performs better with players that they have a connection with, and having a player on your line/pair that makes everyone care about the team provides a spark. To make it super realistic, an anonymous grader will be put into every locker room, and do standard updates as to the team's social abilities. if a player is inactive, his or her line chemistry would go down. If a player is killing it with good music, stories, memes, chatter, he or she would receive a boost in this attribute, which benefits the players around his or her simulated character. obviously thats not a sustainable or reasonable way to run the updates. but involving the mental/hidden attributes is a cool way create some build diversity. maybe there could be standard TPE, and mental/hidden "TPE" where you can check/uncheck which roles your player would have.
Increased "realism" tends to lead to inactivity amongst the lighter users, so box-checking might be the superior option (ex: here are 45 locked TPE that dont count towards your TPE total. distribute these as you see fit amongst these 4 mental/hidden attribute categories)