stalker is not the same kind on RPG and the player action does not have a really big impact on the game, even Mass Effect (which I really really love) seems to be rather poor in term of implications and choice comparing to D:OS
Here's the thing with modding though, we don't have to make it have a big impact if we don't want to so I can see a Stalker mod being plausible, but would need tons of work on importing pretty much just about everything needed (cars, guns, armour, trees, terrain) but it's still possible unless you want real time combat.
