Seems a very reasonable analysis and expectation:
- Slightly above a GTX 1080
- Decently above it in optimised DX12/Vulkan games
- More power use, and hotter
- Likely nip at the heels of the 1080 Ti in a year, and in highly optimised low-level games
So yeah, if that level of performance and potential come in at £450, AMD probably have a winner on their hands.
Ram usage is interesting, 1080ti had the highest ram usage with vega the lowest, close to 1 gig difference between vega and the ti at points.