Honestly, just being able to play as an apex pred would be nice. Whether it would be a 'free for all' style. Or a 'hide and seek' style, which is admittedly. What this game is more centered about in overall gameplay.
But 1 thing in particular still bothers me to this day. Which is unfortunately, a lack of replay-ability. I personally believe that something relatively simple could be introduced. Which are rewards for completing a 'match' against specific preds.
Best example I can give would be a 'Golden/special' apple from escaping normal/nightmare Belle. Which basically grants you a full stomach on nightmare mode. Making pred students a viable option again, rather than heavily relying on 'regular' student. Simply because he doesn't generate extra 'noises' while trying to hide.