Honestly, board play needs the biggest rework. It's a chore right now because you just get warped into the animation and have mindless digging for 10 seconds until someone just pops out with the puck. I'd rather see a bunch of checking animations that branch into "pins" with a loose puck than what we have now. Eliminate the dig element, make boardplay more fluid without removing the ability to cut someone off using the boards.
As far as bridging the balance between realism and "digital hockey" they need to make players feel more unique, they need fatigue to matter more and quicker, and they need to figure out how to have more scrambles and chaos in this game + more dynamic goalies and goals. The game is just flat-out boring because no matter the slider set, the same few goals go in. The AI inevitably breaks down in the same ways, the goalies get beat with the same moves, there's just nothing "random" or exciting about playing real hockey in this game.
I still believe NHL Hitz Pro was the greatest balance between sim and "digital hockey" we've ever seen. Had some sliders that you could tweak to make certain plays more or less successful, but at the end of the day, the action was fast and fun, the defensive AI challenged you a lot with pokes, checks, and blocked shots, the goalies made some incredible scramble saves, but they also had weight and fatigue so scrambles and shots and passes lead to a tired goalie who eventually just got beat to a spot or couldn't recover if you got a rebound and made a nice pass to the open man.
If there's any game they need to model the whole "feel" of, it's that game. So many scrambles, gritty goals, diving shot animations, diving shot blocking animations, it was just really desperate hockey in-front of the net which is what hockey is. If anything, that game lacked the ability to score "pretty" goals which got a little mundane in it's own right, but it's definitely a lot closer to "the real thing" than the current game with 10x the action and fun.