I think it's best not to expect any surprises in terms of the hardware at this point. After Navi is revealed, we'll essentially know what kind of performance we're going to get by looking at the mid-range option (which might still be the fastest Navi GPU they reveal, mind you).
I think what people are going to be impressed by, and this has been the case for every console generation for a while, is the innovation on the software side. Sure, you can't get any more realistic than PBR in terms of authoring content, but all those little things devs wish they could put into their games today will become commonplace and more brutally optimized than we've ever seen them before. Just think of all the beautiful techniques for indirect lighting, shadows, and complex materials you've already seen (sans raytracing) being used together and at higher settings.
And let's not even get started on how insane the artwork is going to look, given the right talent is involved. Actually nevermind, let's. We can already use far more polygons than devs are typically using on current hardware, and a lot of the reason artists aren't going higher is because of the futility of making an overly smooth model without a detailed enough normal map to complement it. Also, many are afraid of vertex skinning costs, but this limit is going to be lifted in a tremendous way with these new CPUs. So from day one, we'll see many of these rendering techniques used together with less pressure for artists to optimize, and without a fundamental shift in authoring tools, leading to an impressive leap in visuals without any new innovations. After all, there are many realtime techniques that have been available for years that devs have been eager to use which the PS4 just couldn't support without aggressive optimization and absurd man hours. Many of these things were only just barely out of reach on contemporary console hardware.
Now, on top of all of that, consider the additional techniques and research that will be born out of an 8-12 TF GPU being the lowest common denominator (excepting the Switch since it requires so much extra work and many games already skip it). While we could certainly use the crazy performance some are daydreaming about, I think a lot of developers aren't even going to know what to do with 10 TF especially when it comes to their artwork. 'Easy mode' would be making the games of today with PC-like settings and more density, which isn't exactly a bad thing, but if a developer really wants to make use of the hardware, they'll be able to blow our socks off.
The primary limitations on artists from this generation will be gone. There is so much short of raytracing that we're going to be happy to have.
