The supposed RX Vega 3DMark11 scores give me a little more hope for Vega. If they manage to squeeze out another 10% through some combination of further driver enhancement or enabling features that aren't working yet, I think it will be able to position Vega squarely between the 1080 and the 1080 Ti, at least in terms of performance which gives it some wiggle room in terms of pricing as well.
The 16-bit float performance also has some good potential for future performance gains, but that's going to be squarely in the hands of developers. If nothing else, it does make Vega slightly more future-proof, or at least gives it the chance to have some legs, a bit like the 7970 which was a card that people seemed to get a lot of life out of compared to its contemporaries.
We may not see AMD be truly competitive until Navi though, but only if they're able to have as much success with the small, multi-die approach as with Ryzen.