I really don't think that 4K shot was far off, if off at all.
Go back and re-watch SoD, seriously pay attention and pause each "scene", you'll find something iffy on just about every sequence. Whether it's a bad texture, or heavy DOF implementation to take eyes off the LOD.
Compare moments we can compare, like the quality of the house where Geralt slices that guys head off and the Inn Geralt/Vesemir enter in the 15 minutes of gameplay - it's extremely similar in quality. The grass in the 4K shot VS the grass in the scene where Eskel igni's the Wraiths - again, very very similar in quality, if not identical ETC ETC.
I think SoD looked fantastic, amazing even, but I think people just kind of blur their mind to the little details because it's all moving so fast and you're just soaking in the general "amazingness" of the trailer. Whereas when you have a screenshot - you just sit there and stare at it until you notice the flaws, or in the case of the big Gamepaly Demos they get scrutinized and dissected much more than a Trailer ever would, everything is moving much slower and it's raw.