I was never convinced that the final game would look like the VGX/Sword of Destiny trailers, even when they first came out. From the lack of HUD, the overly "cinematic" and dynamic third person cameras, crazy amounts of lighting/shadows, just the sheer level of detail in each scene, etc., it resembled pre-rendered cgi more than anything. I'm not even sure if they have a working build at that point at E3 2013 (though I do remember a closed-door event for some journalists which was kept on the hush hush).
What I am really bummed on is that the 35 minute "Gameplay" video is now a pipe-dream. It was a whole half hour long and it came out in August 2014. It may not reach the Sword of Destiny graphics level, but damn did it look glorious(DAT Novigrad). THAT was the product that I was expecting on my laps in March 2015 (this was before the final delay to May, i believe). Fast forward to less than a year later, and that atmosphere is just....gone, with world clutter, foliage, and NPCs noticeably cut down, and a lighting system overhaul that is strangely flat and harsh and paints a layer of mustard yellow over everything.
Platform parity is a thing now for CDPR, but the real gem of the fiasco was of course CDPR's PR doublespeak and refusal to acknowledge or clarify. I held them to a higher standard than that, and that was my mistake. Lesson learned, I guess. Pre-order for me has now truly been taken out to the woodshed, and extra precautions should be taken for any future trailers (looking at Cyberpunk 2077 here).
On a more encouraging note, CDPR seems to be very receptive to mods, and have mentioned that they would like to release a modkit soon after the game's release. Always has that to look forward to.
p.s. I recall a minor ruckus made (mainly on the CDPR forums) when the 35 minute gameplay video was released, about the downgrade from VGX/SoD. Quite amusing when taken in perspective of the final product we're getting.