Honestly, I'd be more interested in a post-apocalyptic game that doesn't rely on monsters. The Road was so depressingly effective (and so effectively depressing) because it was just about society falling apart, without needing a zombie infestation to cause it.
It would make a better game too, in my opinion, to leave the zombies behind; the use of (mostly) inhuman monsters as enemies in this seems like a cheap way to get around the "lead character as murderous psychopath" problem that the Uncharted series has started to run into, and doesn't actually leave the unnecessarily combat-heavy gameplay behind.
If they're really serious about driving storytelling forward, Naughty Dog need to commit to pushing their themes through gameplay, not just cutscenes. The problem with the story in Uncharted 3 is how most of the stuff you play seems non-canon for Drake's character; all the murdering is just something you do to keep you entertained as you move from point A to B.
There's such a disconnect between the flawed-but-fundamentally-good guy you see in the cutscenes and the remorseless gunslinger you actually play as. If that dichotomy isn't resolved effectively in The Last Of Us then I don't think the story is going to have the resonance Naughty Dog are hoping for.