There are legitimate concerns with the build we have information about. That being said, everyone calling for nerfs before the expac hits are a little silly since they'll swing that nerf bat around for sure soon upon release.
It is curious wondering exactly how the Tank Meta is looking to shape up, though. Paladin's DPS increase is welcome, but DRK's dps is arguably worse than it was before, and Warrior essentially didn't change.
I've heard speculation that Warrior could be out of the meta, and that would be the first time since the Warrior rework in 2.1 or 2.2 or whenever it was that Warrior hasn't been viable. It's interesting.
Speed kills are a thing also, so finding the optimal comps for this and early completion of raids is going to be a thing. Meta doesn't matter for most content in the game unless you're bleeding edge, and that's a very small fraction of the community.