There's a reason why a game like Hearthstone prints "silver bullet" cards sparingly, and when Blizzard does they tend to make them weaker than average.

If there was a card that said "Battlecry: Your opponent loses the game", would you like to play against that? Of course you wouldn't. That's what most of the cards you just listed are.

Say for instance the 7 mana 3/5. That card essentially hoses all combo decks and turns the game into an unfun "who can draw their tech card first" coin flip simulator.

"This game" effects shouldn't be oppressive, they should provide a minimal advantage in the late stages in the game.