CaptainTom :
-10-15% performance makes it only 10% stronger than the 980 at most buddy.
Using GDDR5 would give it only like 10% more bandwidth then the 1080 with its GDDR5X.
What your describing is a card that is only 5-10% stronger than the 1080. Let the dream die - 1080 Ti isn't coming.
I also think it will be a hard sell, given the performance difference between the 1080 and the Titan X (Pascal)... BUT! You're missing the price gap difference. Thinking linearly, and given recent nVidia history, they can still place a 1080ti right when you're saying would be dumb, just because it would be justified by a price scheme perspective.
Like the article states: "Value? What value? This card is not about value". When you put a product that performs very similar to another product that "escapes reason", then it becomes "very reasonable". It's marketing shenanigans, but they do work, unfortunately.
Cheers!