The common theme of all these articles is the depth that Deus Ex had, a depth that few other games have even attempted. Maybe nothing better represents this than the political philosophy and literary connections made throughout the story and world.
The game uses paranoia to encourage the player to think about what's going on. It doesn't just hand you a world, expecting you to accept it and move on. The game forces you to confront and think about every aspect of it, really think. Bioshock did something similar, for a more recent example. What's the difference between a conspiracy and a government? Do you know? What about between a freedom fighter, a soldier, and a terrorist? When does security destroy freedom? Is democracy a good thing? How much evil can you accept if, in the end, it's for the greater good? Can humans rule themselves, or do they require external authority? Is mass communication a good thing? When do we stop being human?
I could wax on, but instead, I'm going to quote the game at you. This is just a small sample, but illustrative of the quality of writing (and the thought behind it) that we're dealing with in Deus Ex.
"When government surveillance and intimidation is called 'freedom from terrorism' or 'liberation from crime', freedom and liberty have become words without meanings."
"When due process fails us, we really do live in a world of terror."
"Every war is the result of a difference of opinion. Maybe the biggest questions can only be answered by the greatest of conflicts."
"What good's an honest soldier if he can be ordered to behave like a terrorist?"
"Somehow the notion of unalienable liberty got lost. It's really become a question of what liberties will the state assign to individuals, or rather, what liberties we will have the strength to cling to."
"Being a soldier isn't just following orders, it's following those orders in the service of a higher cause. When that cause is betrayed, we're not soldiers anymore, just pieces on a chess board dying for the wrong reason."
"I guess it's not surprising to find a few crooks in a place protected by security procedures. The shadow of secrecy... it protects indiscriminately."
"There's a time and a place for security, but the legislature has to stay vigilant, or there will be abuses."
"The checks and balances of democratic governments were invented because humans themselves realized how unfit they were to govern themselves. They needed a system, yes. An industrial age machine."
"Without the use of computing machines they had to arrange themselves in crude structures that formalized decision-making. A highly imperfect and unstable solution."
"The human being created civilization not because of willingness but of a need to be assimilated into higher orders of structure and meaning."
"God was a dream of good government."
"The individual may be remembered, but the organization persists and thrives. A single artist, a single general, a single hero or a single villain may all die, but it is impossible to kill a people, a nation, an idea - except when that idea has grown weak and is overpowered by one that is stronger."
"Listen to me. This is real freedom, freedom to own property, make a profit, make your life. The West, so afraid of strong government, now has no government. Only financial power."
"A system organized around the weakest qualities of individuals will produce these same qualities in its leaders."
"You can't fight ideas with bullets."
"Ever wonder why big car corporations pay two percent tax and the guys on the assembly line pay forty?"
"Corporations are so big, you don't even know who you're working for. That's terror. Terror built into the system."
It's a game, not Plato, but the fact that they were even willing to try to add real depth and thought to it deserves respect. Modern developers should pick up the torch.