Warmongering in modern times is much more of a challenge than it has been in the past, thanks to the internet allowing for a near instantaneous global transfer of information.

This has allowed people from all across the world to directly connect to each other, circumventing the government institutions and traditional media outlets on which we used to rely for information about foreign powers. This helps us to see past the world's invisible boundaries and realize our similarities as humans, and it allows us to see through the deceptive reasoning governments once used to call its people to arms.

Even if the brains behind some Western powers decide they want to start a war for whatever reason, the peoples of those nations are gonna be like, "What? That's stupid. We don't wanna fight them." They'd never get any support for it.

I could see an isolated war against a country like Iran possibly breaking out at some point, but even that seems unlikely in the current climate, given the realization by most that the reasoning behind the war in Iraq was shaky at best, the fact that Iran isn't really a threat to anybody aside from its direct neighbors, the increased spread of information through social networking and sites like Wikileaks, and people just being tired of fucking war.

I find it amusing. If one of those countries (Iran, North Korea,etc.) made a similar game where the enemies were the Americans, Fox News would have an entire piece on video games that are being used for terrorist training.

Mind you US are not by any means weak and they can pose a long-term threat. But if you're exepcting a clash of million-sized armies or nuclear armageddon, I'm afraid you'll be dissappointed :D Other than that world war is very possible scenario.

Perhaps in some sort of slow burn, similar to the "war on terror"

That's just for occidentals' pleasure : occidentals prefer to shoot at the classic Nazi, Russian, Talibans, etc. than on their own people ! I don't think there's any propaganda and people are not that stupid, we know that US gov/powerful people are bad and lied on Irak and surely on Iran. Thanks to Internet we are all more well informed and have other sources than the pitiful/propaganda classic corrupted media.
I'm not racist but personally I never took more fun than shooting at Africans on MW3, that was so unusual and they're so real and fun in the game, they even speak an unknown language in a fun way (or is that French with a strong accent I didn't even noticed even if I'm French ?)

Slow burn (aka partisan war, low-intense conflict, counter-terrorism operation, war without frontline, "anti-papuan" war) like current Kenyan-Somali war... yes, it could be, but not exclusively. For the most part it'd be a series of short burst (couple of weeks , a month or two) of high-intense conflicts and god knows how long low-intense phase like recent war in South Sudan or military operation in Burkina Faso. Seemingly regional conflicts with global aftermath and quite possible involvement of the "tough guys" at the peak of all these mess.

Say, atm I'm monitoring all freely available info coming from Karabakh, and by the looks of it there'd a second war before year ends or next year at the latest. Needless to say that these guys have serious grudge over each other, in a sense "final resolution" of Karabakh issue was part of election campaings for both Aliev and Sargsyan. Obviously Azeri have far more reasons for militray escalation in the region, because Armenians kinda won last war, so they're bumping up their military budget sky high hoping for a cake walk when the war bursts. Could this particular regional conflict lead to Iran, Russia, Turkey, Kurds, US involvement? Easily.