It doesn't really matter what retrospective claim the devs, or you for that matter, come up with to explain away a bad decision. They could have assigned extra dps to all jobs containing the letter 'm'. Hey look, that fits too. If you don't offer people a reason to want to tank, they won't tank.

And right back at you: why don't you wait eight weeks for gear, then, if it doesn't matter so much? Let's aim for a scenario where tanks get gear over dps then, if you're indifferent to it.