Moonkin Form now grants 15% damage reduction instead of increased armor.
See, what the armor bonus did was allow you to put together mitigation gear, just like any other tank or off-tank. Now, the benefit is flat. I'll have to double check the mathes, since I really am mostly a non-mathes player, but I don't think 15% is going to be as good as max leather armor with the proper enchantments, etc.
This is really another watering down of the game, "Dungeons are hard" aside. Not only does the quest reward gear look exactly the same with small changes during upgrades, saying that you're essentially marching your way through a pre-defined route of gearing when questing, now, just as with the switch from +healing gear to just generic spellpower and the elimination of spell type specific bonuses, every Boomkin is marching along, playing just like every other.
The character of the game is taking a hit. Playstyles are becoming more standardized by the standardization of gear and gear bonuses.