They're doing what I felt like they should've done from the start, mimicking the class balance of the each patch. The current "the last patch balance and that's final" paradigm has come to an end.
Perhaps we've finally hit the point in the game system where the developers feel that they're able to pull of these changes, maybe they really like Mists of Pandaria as they seem to have favorites, or perhaps Blizzard feels that the mists of pandaria has a chance to make it big so it warrants investment.
Also the militant, loud but influental "no chances" grognards are already in their containment zone in era or private servers.
I just think it probably wouldn't have been that much of a hassle to put some sort of aura buff such as -10% damage to mortal strike and come next patch set the aura to +-0% damage to mortal strike.

Also interesting is to note the completely different approach to balancing the game between the Aggrend, Ghostcrawler and Ion Hazzikostas.
Ghostcrawler played holy priest, and holy priest sucked as long as he was in charge. Same with Ion, he played restoration shaman and the rshaman was always the punching bag
until he retired from raiding and they got a massive overhaul in the dragonflight.
But Aggrend has no such qualms. He plays retribution paladin and he will buff his class and spec.