Doug, thanks for a great review! This sounds like it'd be great for high-mountain gnarly stuff.
As for moisture, breathability, and condensation: I noticed that in the set of 4 photos showing the poles there is clearly condensation in 3 of 4 photos. There is also clearly water beaded up on the blue fabric in a photo lower down; not sure if the water running down the sidewalls is inside condensation or outside moisture.
My recollection is that Epic is more breathable than eVent, potentially by a significant factor. It reminded me of this older thread; check the 2nd table by Mr. Nisley. http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=18298
The door design is absurd in many respects. If you knew you were only going to use the shelter in full-on winter conditions, you wouldn't be worried too much about falling snow getting in and out. But rain, well, that would stink. I would also think the flatter roof would tend to channel or pool rain on the roof and around the door zipper.
In addition to snow load concerns on the roof, I wonder how the flat surface would take strong winds? As mentioned, any way you slice it this is still a much beefier option than a standard bivy.
Cheers!