Too early because they are setting the same precedent they set with the last two expansions. They drop the first patch too early, then it leads to a long content drought later on. They can't give new patches every 2 months (at least they never have been able to), so the concern is that we will see the same thing as the expansion goes on, longer and longer patch cycles because they aren't spaced properly.
I mean I'll be happy to eat these words if Blizzard can really generate patches more frequently. Praise be. But history has shown we shouldn't hold our breath.