I think people are too hung up on what they
imagined in that original trailer, versus what was actually in it...
The original teaser wasn't necessarily fully a "dark, gritty fantasy" as in a photorealistic, gloomy world (and it's not like the actual gameplay reveal trailer is all sunshine and rainbows...) It still always had that embellished statue on the hillside, it still always had that weird not-real look to the establishing shot of the canyon, it had that cool but obviously bogus effect where one torch lights up an entire cavern, and then we see nothing of the final monster, just a lighting effect in the darkness. It still was always affected fantasy, not gritty. The lighting in the teaser generally favored greys and shadows, but there's basically only four shots in that sequence, whereas there's a lot more (and more from the ground-level of the player's perspective,) so lots more places for the chosen visual style to go wrong. There's no sequence in the gameplay trailer which has that pitch-black darkness of a cavern with 2 lightsources like the teaser, but that's not to say they couldn't turn lights off if called for. At some point, it's got to be a video game that you can play for 100+ hours, and the overall look flattened out and shows more seams.
We saw that original clip back in 2020 and extrapolated what it meant for a full game. (And imagination was especially uncontrolled back when we had high ideals of what "true next-gen" might look like...) Go back and look at it though; even at the time, its look wasn't fully cohesive or without quibbles.
For sure, the complete style has evolved over time, it always does (and it
still is evolving in active development,) but I would be surprised if the developers actually considered there to have been a radical dustbin-and-restart redesign of the look from 2020 to 2023.
COMPARISONS: