I feel like there's one simple point that needs to be raised in this thread that somehow hasn't been brought up at all:
Cthulhu by Torchlight.
I feel it's very telling that Mearls wants to criticize 5e control spells, yet a book he helmed has spells that impose crippling effects on enemies—stuff from locking down an enemy's spellcasting, forcing enemies to automatically use weak attacks, outright insta-killing enemies—that completely ignore 5e's balancing mechanics for control spells. There's no saving throw. No form of resistance whatsoever. Cthulhu by Torchlight has a spell that kills literally anything after three turns—there's no way to any monster, even legendary monsters, to resist this effect.
Mike Mearls wants to declare 5e balance bad, yet he's happy to purposefully break the balance of the game to sell his own product.