Having just played Lords of Shadow 2, my first response is:

However, having just beaten The Last of Us last night, it's actually a pretty intriguing idea. It is possible to create beauty in a post-apocalyptic landscape, the problem is game developers tend to go the easy route and either set their games DURING the apocalypse, which means lots of rubble, fire, smoke, and charred buildings, or in a dry, flat, brown world to get the whole "THE APOCALYPSE HAPPENED, CAN'T YOU SEE" statement across. The Last of Us chooses to focus on the "post" rather than the "apocalyptic". Darksiders also had the right idea, blending the modern cityscapes with overgrown foliage and fascinating demonic landscapes.
I think it could be a very well done game if designed right, but the artists would have to steer away from the urge to pull the (yes, I know this is sacrilege)
always night, Gotham City look, or the desolate Fallout look. Make a game about vampires and other monsters? Sure, then actually play with the concept of nighttime and daytime to make nighttime that much more terrifying. It was probably one of the best things about Simon's Quest, and setting your game in perma-night is always going to look duller and greyer if the setting takes place outside, because that's what night does. Light makes things colorful, night makes things not colorful, because color is reflected light.