Just for context, the top 25 cameras evaluated by a third party are these:
https://lh3.googleusercontent.com/-...eivYBNmLsd9dCCESsp6aQCL0B/h871/2016-10-15.png
This year's best Samsung camera is 1 point above last year's best, 87 vs 86. I fully agree that Samsung will probably improve upon their already fantastically awesome camera.
The Nexus 6P is currently in a 5 way tie for 12th place, while the Pixel is alone in 1st place (as of 10/15/2016).
So it'd be impossible for me to reconcile there being no evidence for the Pixel camera being better than the Nexus 6P. It's also extremely unlikely that Samsung will blow anything out of the water, since the last three years of major players in the camera arena are on this list and there are very few stories evident in this data other than iterative improvement. I wouldn't put it past them to get an 89 or maybe even a 90, but outside of that it'd have to be a major change in technology, not just choosing a better processor, SoC and writing better software. It's also entirely possible the S8 will launch with a camera that scores an 86. Difficult to know without having a phone in existence.
For example, the S7 Edge is slightly better than the S6 Edge Plus which is slightly better than the S6 Edge which was equal to the Note 5 which was a big leap over their 2014 best, the Note 4.
Another example, the iPhone 7 is slightly better than the iPhone 6s Plus which was slightly better than the 6s, 6 and 6 plus.