First if all I will say that I really liked the idea of the new quests that didn't require you to just win with some classes, and personally I enjoy building and playing decks that otherwise I wouldn't try.

What has happened in reality is that the casual queue is full of people playing completely uncompetitive decks that have 30 battle cry minions/ class cards Etc. who just dump their hand every turn and then concede whenever they can't play any more. For me the casual queue was a break from playing against consecutive tryhard, unfun netdecks on ladder. Now I can either play against Shaman all night, Secret Paladin (Wild obviously), or completely useless quest decks. None of these options are entertaining to me and I often quite playing after a handful of games nowadays.