I really hope Happy City returns to 3 player in arena or goes to a rotation, but seeing as how it has been 2 player for 6 months I am not going to hold my breath. Instead I would like to ask if we can have the developers give an option for removing certain cards from the deck in 2 player. There are a couple that make the game unbalanced, the biggest culprit is "Versailles Palace" (which is the steal a coin bonus card). In 2 player if you get this card you will almost always win. I think I have seen only 1 game ever where the player who got that card in 2 player did not win.
I did fill out a suggestion, but wanted to see if there are other cards that arena players dread when they see (especially if they are going 2nd).