I thought a bit about what is missing in this game and I came to one conclusion:
Player specialised Perks!
Some player like to play with casters, some are most direct bashers, some like regenerating and other just want to tear the whole dungeon down.
But all players have to use the same Classes and have no possibility to specialise on their playstyle.
So it would be awesome to have some kind of triple skill challenges that give you some special effect (like +1 reg per black tile, +1 mana on wall destruction) that you have to use cleverly to solve that challenge. If you can solve this triple challenge, you have to choose between these three perks. The chosen one stays permanently on your account for all additional dungeons, the other ones are gone forever.
This happens about 5 times through the whole time, later perk challenges even starting after Purist GoT to give some kind of end game progression and give a reason to replay the game just to try out another style of playing.
What do you think about that idea?