If they're postponing Tanaan to get the expansion out faster, I think they have the potential to release the expansion in just a few weeks: one zone at a time. Frost/Shadow in early Sept., Talador in late Sept./early Oct., etc...
If the goal is to get WoD out as soon as possible, and they're already cutting into the mainline continent, what could a method like this hurt?
Would you support an idea like this? Personally, I prefer that they take all the time they need, but if that's off the table, I don't see a tiered release schedule being any worse than what they're planning now, especially if it accomplishes their goal of releasing the expansion faster. What do you think?