those games didnt look worse after the change 

Define worse and be specific ... 

graphical quality

The final product is different than a mockup from three years ago? Goodness.

This is one area where developers have to be very frustrated with the entitlement of some gamers.

(Developer show cinematic teaser video)
"NO! We want gameplay video! Show us gameplay!"
"But ... but this is still early development, so many things will change ..."
"GAMEPLAY!@! STOP LYING TO US WITH CINEMATIC TEASERS!!"
"Okay, then, if this is what you want ... here is some mockup gameplay we put together using projected settings. The finished project is still years away, though, and any number of things--."
"WOW, THANK YOU!"

(Game launches)
"What the hell! This is a downgrade! THE SHADOWS ARE DIFFERENT!!"

@Bold Again with the vagueness. BTW it's "emssive" light that their showing and it's still in the game ... 

Define "interacting", practically all lights in every AAA engine are interacting with the materials to do some physically based shading. "Hand program" shadows ? Do you mean pre-baked shadows or the global illumination, well what is it exactly ? 

For the reflections do you mean you have to bake in the cubemaps ? You don't have to do that anymore but most of the reflections shown in the original trailer are "screen space" and are available via the "Local Reflection Quality" option on PC. 

Both the game and trailer are very far away from "realistic" since they don't even do any form of ray tracing that is not in screen space so judging the accuracy of both is moot ... 

I'm pretty sure I remember people here crying downgrade against Quantum Break here and I also remember some saying Killzone Shadow fall getting a downgrade too... 

OK lesson learned for me here, don't trust a lot of the people here to even give an analysis ...

I mean they're using pre baked lighting in the release.

But, just for shits.
:20 map changes from what is a very intesive looking map, to a 2d plane.
:40 steam from ground iluminated by brake lights, brake lights on release dont reflect or glow against nearby objects.
1:20 smoke and wind effects on nearby building, wind absent from release, smoke is lower quality
1:34 draw distance
1:40 lack of lens flare effects, and quite a lot of them
2:15 fight, lack of hard shadows under characters, replaced by fuzzy haze; also, lack of cold breath steam from breathing
4:30 area is completely different, no light trails in hallway or sequence event with the swinging light.
5:18 "check out manhattan" now replaced with fence because draw distance doesn't extend far enough to show good detail

Pre-baked where exactly ? You can't exactly pre-bake when you have a day and night cycle but according to their GDC presentation it says their using DYNAMIC Global Illumination but I won't deny that they could be using some sort of pre-computation like Quantum Break does ... 

1. I'm pretty sure we were talking about the in game graphics so it's pointless to argue about map design ... 

2. Does it matter ? Smoke or other participating media can still receive lighting. What makes car lights or any other generic spot lights in the game so much harder to handle ? 

3. Wind is not absent from release as it is in the graphical options and how would you know that the smoke is lower quality ?

4. Draw distance ? I know that both are pretty high and if you stop at 1:39 you'll see some buildings occluded by the fog so I'm not exactly sure what basis you have to say that it's been lowered ...

5. Lens flare is still in the game, just find a strong light source to activate it ... 

6. What fuzzy haze ? You mean the ambient occlusion ? BTW there's still projective shadow maps in the final build from the frames 2:16-2:18 on the left, you just have to find the right lighting conditions ...  

7. Your point is ?

8. Nope, the fence only partially occludes the view but if you look hard enough you can still see the distant buildings ...