Request: Prevent starting game without hero or another specific card type.
Just a small suggestion that would be useful for the problem people are having of starting games without the hero card and probably even other game types.
Add a field when creating a game mode game mode that can either be empty if you don't want that game mode to require a certain card type to be present (king or hero for eg) and if you don't have the card type specified there in the deck prevent the game from starting just like it happens when you have too few cards in the deck.
Something like this. I feel like this wouldn't affect existing games and it would help others so no harm in it.