World War: Norrath

[Xanthias]

The first way I would look at this is defense of home first before expanding into other territories.

Barbarians - Think Russia during WWII, they can give up territory that is basically useless until their someone finally reaches Halas. They also only have one front to defend.

Dark Elves - One Front to defend, home city has one entrance that is easily defended, plus they have access to almost all classes.

Erudites - One front, but the problem is two factions that will try to eliminate each other before moving on.

Gnomes - One entrance, however like most of Faydwer it is going to be a mess between elves and dwarves plus you would have issues defending from MM and Crushbone

Dwarves - Kaladim is a death trap waiting to happen, they also control access to Antonica, but at the same time it opens a second front for them.

Elves - Kelethin is great for defense, but fire and trees bad. Felwithe is a castle that could hold out, but they have the same issue the Gnomes would, several armies could basically lock them within.

Halflings - Kithicor is a natural barrier for most attacks, however the close proximity to High Hold Keep, Neriak and Freeport makes them into an island.

Ogres and Trolls - Seriously if they had their intelligence from before the great wars with the Gods they'd be a threat, but right now they're cannon fodder.

Iksars - A continent to themselves lots of territory between them and the other races would allow for them to amass an army, the problem is getting their forces to where they could do the most good. Invade Oasis you put yourself between two parties. Invade Faydwer and you might be able to get a foothold, however you'll have to defend your back against Dwarves or Humans from Antonica.

Humans - breed like rats, spread out all over the place, Freeport would be inflames due to infighting. Qeynos would hold for a while but the Mongol/barbarian horde would eventually get down there to destroy it. The last bastion for humanity might just be HHK.

Conclusion:
Barbarians would probably control the western side of the map, humanity locked into HHK, the DE's would sweep down from Neriak to take Commons, Kith and Rivervale, plus working into Freeport the Oasis etc.
Innothule and Feerott is just a mess and probably where the Iksars would go upon landing in Oasis to set up a permanent base.
Faydwer would end up being holding actions between the High Elves, Dwarves and Gnomes as it would be almost impossible to get inside the cities.

It would be interesting and ugly at the same time.