Considering that Duskmourn: House of Horror, has made milling decks laughably easy to create, and laughably powerful, I'm gonna bring up ye ol' faithful suggestion. Milling decks, should punish the player doing the milling as well. If you're playing ranked, you should not be able to mill your opponent to death, simply because you're lazy, and don't want to actually play the game. These decks ruin the fun of the game, are extremely lame, and Scrabbling Skullcrab from Duskmourn: House of Horror only amplifies the issue that is milling decks.

Something needs to go, and in my opinion, if you mill an opponent for too long, some form of penalty HAS to occur to you, because it's extremely boring for the opponent to sit there, and not be able to play because of an unbalanced deck, revolved around a laughably boring mechanic.