Faction warfare has been slowed down a lot with the latest patch (Cthullu). I'm currently in mid-February, researching endgame tech, and the factions have barely hit -50 opinion with each other (war threshold is -75). At the current rate I should be able to finish the game before the faction war starts.
Which is good, because with the new patch the doom tracker has been replaced with a "human survival count" on the strategic map, and you lose if the global human population dips below a certain percentage. The game would be REALLY hard if you had to somehow stop the three groups murdering each other while somehow keeping them all alive. As it is, my current survival percentage is 70% or so, which is nowhere near the 20% mark that causes you to lose the game.