Matjillam - I'm actually playing a game right now like the one you suggest. I've always preferred building/peaceful games, so wanted to try my hand at a war-filled game.
I put on aggressive AI, and only conquest/domination wins. Genghis, Monty, Alexander, Shaka, Ragnar, Napoleon, Toku, and I threw Gandhi in for fun. I'm Genghis, and it's actually been a brutal challenge. Apparently, all the warmongers are best buddies with one another...every time I DOW one of them, I get negative multipliers from the others about DOW'ing one of their friends. I took Ragnar out early (and paid for it with a dead economy for a long stretch), and Alexander and I wiped out Toku. Poor Gandhi was the tech leader early, but apparently everyone went to war against him at the same time and wiped him out.
So I'm left with everyone furious at me except Alexander (who backstabs anyway). Shaka is the tech leader, and most powerful, but he's furthest away from me, so the least of my worries. I have Alexander, Monty and Napoleon all next to me. Alexander keeps declaring on me when cautious. Once I make peace with him, Napoleon declares. I just took Paris and Orleans from Napoleon, seriously weakening him, and of course, while my troops are healing in Paris, both Monty and Alexander DOW on me on the other side of the continent, so I'm racing everyone back to try to save my cities. It's clear I'm going to lose at least one, but if only one, that's ok - two steps forward, one step back.
With my weak economy for such a long stretch, I had to alter my teching strategy - no chance to hit liberalism first. I headed down the chemistry/steel line to get grenadiers and cannons, instead of cavalry and riflemen. It's going to be a long game though, since all we do is warmonger the whole game. I do have one incredible military city though - all the GGs Genghis produces have gone to that city. Heroic Epic, military academy, vassalage, theocracy, and 6 settled GGs make for one ridiculous military production city.
It's a lot of fun, and it's pretty clear everyone isn't thinking about space, but it kills me that all these warmongers are best buddies - they're all ganging up on me!