I've always liked the idea of personality attributes to build more character around the skaters.  Specifically, I'm looking to build how my skater plays the game, not necessarily how well they perform the actions they take.

For the sake of discussion, I will just use EHM attributes as examples for the types of things I'm looking for.  Personally, I would love to build Slip McScruff kind of like Zdeno Chara and invest in Teamwork, Influence, and Bravery.  I wouldn't invest in things like Creativity or Flair.  Someone could build a super star goal scorer that has high Creativity, Flair, and a Shooting Tendency but they would skip Teamwork, Bravery, and Aggression.

While the idea of mental attributes isn't super original, I would love to come up with a system separate from TPE so you don't have to choose between building your personality and building your skillset.  Especially at the beginning of NSHL, I wanted to do the Chara build from above, but needed to build up my skillset to be relevant.  Instead, I would want this personality system to be based around experience in the league.  This would be like the veteran in the locker room, their physical skills may have regressed due to age, but they still have more experience than the rookie.  They know themselves better and have an established style, whereas the rookie may still be figuring that out.

So maybe at the end of every season, you earn some number of points that can be applied towards your mental traits.  Different archetypes can have different starting mental traits too, so a defensive defensemen might start with more aggression and you have the option to temper that over time to reduce the amount of penalties you take.  Whereas a sniper may start with lower teamwork and you have the option to become a better team player or stay as the finisher.

I'd think winning the cup or losing in the finals would be a strong learning experience, but I'd be concerned with already successful teams snowballing based on success.  That could work paired with something that makes it harder for teams to stack their lineups, like a higher minimum salary or a smaller cap.  It could also come from IIHF play, but then we have to account for teams like USA and Canada where it takes longer to make the roster.