Yeah, its the HBM decision that has limited their adjustability on price.
It is pretty clear to me from the reviews that if you are looking at a 1070 class card that you are better off buying a Vega 56.
The 56 reviews are a reminder of the limitations of the 1070 card, especially when you get closer to the metal, where the 56 card gets close to the 1080 and in the case of Doom, actually beats the stock 1080 whilst pumping out over 100fps at 1440p. This is a clear indicator of the future performance of the card, no doubt the result will be repeated with Star Citizen and the new Wolfenstein game.
The 1080/64 decision is much harder because the 1080 AIB coolers are so good, no doubt the AIB 64 cards are in the wings but really it looks like Vega needed the extra cooling from day-1 due to the noise output.