I feel that it won't be overlooked, therefore 1070 will cost at least £349, 1080 - £499 or £549. Then in 2017 GTX1080 Ti will cost - £749, and the new Titan - £1299, hence HBM 2.
Turns out that it all is coming true. http://www.gamersnexus.net/news-pc/...080-founders-edition-and-reference#!/ccomment
There will be only one reference GPU version of each and 1080 will cost about £550. Ti will definitely be more expensive that £700. HBM 2 alone will cost a cow for us so I think that even £850 ($999) for Ti is a possible price tag as the Titan X costs that much now. Of course not many people will pay that much (only enthusiasts I guess) , therefore their next gen cards 1170 and 1180 will give the performance of 1080 Ti for half the price.