Because so far things I would change would be this
-enemies reacting to damage moriré realistically
-weapon tweaks
-armor overhaul and a change to a much less ficticious version
-remove the story
-keep the origin of the zone to be a extraterrestrial “picnic on the side of the road”
-add more voice lines
-shader changes specially fixing things like flashlights
-add more effects like dust
-remove as many ui elements as possible and change them to more immersive ones
-medical overhaul
-add veichles
-change the way items can be found
-alter the map layout and Easter eggs
-coop
How plausible is all this, would the dev kit be powerful enough to allow it or would it be like metro exodus dev kit in wich you cannot edit stuff like Champaign