Cutting down for consoles can go beyond just graphics. There are some things that would require fairly fundamental differences that, if the PC were to be fully supported, would require significant amounts of work. The most obvious example could be things like the size of maps and so forth because PC's have many times more memory than consoles. That's usually a restriction you have to design to from the outset.
That being said, as others have pointed out, the thing that really breaks console ports is the UI and control function and layout.
I have faith that they'll do it right though, but man, they're going to have to spend a hell of a lot more time on QA and testing than they have in the past. I can't even imagine the sort of rage we'd see if a console game came out as buggy as past Stalker games were.