Well I have now played two 3 player games, and this is my 2 Canadian cents.
All games were played with the 2+ condition for Khorne and Slaanesh+nobles+heroes.
The first game was Khorne, Nurgle and Tzeencht(me). Khorne had a pretty tough time at it, since I was able to move his forces out of my regions and alternativly move all but one of my figures away from his most of the time. Nurgle got off to a shaky start but eventually he got the hang of corrupting and dominating. I having the insidious advantage of having read the rules twice and having favourable Old World cards won through dial threat. Nurgle got a few ticks and Khorne got one.
The second game had Khorne(me, wanting to see if his dial condition as +2 plus was too weak), Tzeencht and Slaanesh. Except for one turn I always got and rick and got 2 ticks twice. Tzeencht was being very mild and therefor got few points and ony 4 ticks by the end. Slaanesh got around 20VPs in the last round of the game pushing him to close to or above 60! He would have won but Tzeencht tied him for most dial tokens preventing him from gaining a threat victory tie, therefor allowing me to ****** victory by a mere technicality! Oh he was not pleased at Tzeencht or me.
So what I got, admitly from 3 player games only, is that the 2+ condition does not hamper him more then anyone elses. It is more on how you play and especially how the others play against you. If 2 or more players gang up on you, it is very tough to pull off a victory.
Slaanesh's 2+ dial condition appears to me as the hardest but he is not reliant on it as he can dominate/corrupt the crap out of a region.
I would like FFG to post a quick answer as well since I am running this game at a con this weekend. I will be using the 2+ condition for everyone unles FFG says otherwise, but I hope they do not. (I admit if during the con Slaanesh and or Khorne get hammered I might change it but I am of the mind that at least Slaanesh is meant to a bit more tricky of a God to play then the others.
ps. Does teleport work on enemy figures? I assumed it did as the text does not say "Your figures".