You should read Triple Canopy if you aren't already, or at least this one article that has special relevance to video games: "The Anatomy of Ruins," analyzing our relationship to ruins and what that means.
In video games, that usually means romanticizing them in some way, making them oddly beautiful or otherwise visually arresting. It makes sense, after all, seeing as the vast majority of FPS games are about destruction and the spectacle of the remains. And, well, guns and explosions and things that go boom.
Some games (World War II-themed games, Fallout 3) are content to use ruins to demonstrate some mundane truism like, "look at all the destruction that war has wrought -- look at all these empty houses! Man, war sucks and displaces innocent civilians, even if you do believe in a theory of just war!" Indeed, war can be pretty bad.
The Halo series and the Elder Scrolls: Oblivion treats the ruin as a mysterious "other," the result of an alien civilization that had strange uses for these ruins, uses that we struggle to comprehend.
Other games celebrate the ruin as a reflection of player agency: the Red Faction series and the Battlefield: Bad Company series come to mind. In it, the player actively creates the ruins. Red Faction celebrates it as revolution, Bad Company treats it like good ol' fun.
Half-Life 2 manages the feat of accomplishing both... sort of: you begin in the derelict remnants of an Eastern European city. The structures are intact, but the social fabric of civilization is in ruins and disrepair. Then, when you return later and the city is in ruins -- specifically a setpiece where fellow rebels tear down a Combine screen in the plaza amid cheers and applause -- it is both liberation from the old world / the oppressive new world order.
(Well, technically you, the player, aren't really doing much destruction. Everything is scripted. Some wood panels will be unbreakable; others are scripted to break the instant you walk over them. TV writers would call this an instance of "fridge logic" that nearly all players take for granted even though it's so stupid.)
Or maybe it's because we can't actually explore these ruins in real-life because they're locked behind rusted chain-link fences, or maybe they're structurally unsound and they will kill us.
Along those lines, I think the Thief series is one of the very few games that treats a "ruin" as something dangerous that may kill you. The Bonehoard? The Lost City? Return to the Cathedral? The Cradle? Any number of fan missions? Your player character, Garrett, actually says on occasion -- "I don't want to be here." They're stark contrasts to the warmly lit art deco mansions filled with gold.
So yeah, those are my thoughts as a player. Ruins are cool and gee-whiz groovy, provoke all kinds of emotions, etc. But as a level designer, I have mixed feelings about it all...
I see it as a kind of artistic anxiety with ruins: you're destroying the level I worked so hard to build.
As more and more games feature "level design" as a mechanic, a game inside a game -- or worse, level design as an automated, procedural process with little or no human artistic input from a designer -- will level designers be obsolete, or is the distinction between player and designer going to be obsolete, as in games like LittleBigPlanet.
Modern warfare, supposedly the inspiration for today's multiplayer team-based shooters, has moved far beyond the static environments of most FPS levels; in fact, the Israeli special forces actively avoids the formative architectural vocabulary we use to layout levels.
Using streets, sidewalks, hallways, doors, stairwells? Ha! These are all obsolete and expected modes of human interaction with the built environment. The Israeli special ops would say you're enframing yourself by using that door.
Indeed, the cutting-edge of modern warfare is about wall-hacking and ignoring the "designer's" intent.
So what is the role of the level designer, when or if the majority of military FPS's make this paradigm shift, when physics engines can finally simulate full environmental deformation, when the mechanics of navigating a level are all about flouting it entirely?
I'm not talking about letting the player crawl through a pre-placed vent instead of using a door; I'm talking about the player creating an entire underground tunnel system. By themselves. With a shovel.
Why do we build a chokepoint into de_dust if the CTs will just blow a hole through the wall above the tunnel? Will we "flag" certain walls as "unbreakable" -- "click here to set a breaching charge on this specific section of brick wall and only this one!" -- or is that desperately clinging to a notion of static level design amid a raging ocean of new mechanics and opportunities for emergence / player creativity?
You can already sort of see this ideological conflict in the design of the Lego Universe MMO. Watch some of the gameplay demo videos: they demonstrate these boring authored quests with tiered goals and achievements and blah blah blah... with none of the actual playfulness of the IP it is licensing. "Hold the Spacebar to build this pre-made model instead of your own!"
(Actually, a better multiplayer game based on the creativity of Legos already exists. It is called Minecraft. To a lesser degree, there is also the MMO game "Love.")
Maybe players don't really care for this kind of freedom? The suspension of disbelief, the ignorance of real-life military tactics -- the invincible wooden door that will never yield to your rocket launcher... maybe we can just dwell in this wonderful dimension of fridge logic forever?