I'm not one to go all squeamish in a game. There are good guys, bad guys, and those in between. And in the end, it's just a game and, as far as I know, no orphan souls are being used to power the servers.
But, the "Evil Elves" in Warhammer Online are pretty evil. And I'm not talking about concerted evil as a crusade against the other side which is good. I'm also not talking about "take over the world" evil. I mean "the script says really really really REALLY evil, so I'm going over the top" evil. We're talking about total chaos. To the point that after I was in the second zone, I seriously wondered how these guys manage to stay together in an organized group. It's rampant chaos and random acts of violence. Does the extra step of sticking heads on pikes really help our side? Or is it just busy work? If I were an evil elf starting up the chain of command, I would think that after a while I would look around and say, "Maybe the good elves are right, I don't need every single commanding officer telling me I'm worthless and I'm a jerk. Especially after I just helped them out and saved their ass or whatever." The defection rate has got to be really high.
I spent time on a low level quest poisoning someone, then covering up the attempt, then taking credit for killing some random dude who is being blamed for the covering up of the attempt. Even the Klingons figured out it was easier to just kill people and say, "He sucked and I have some better ideas" than to try and write plots for a CSI show. Evil for the sake of evil just isn't a good system of governing.
I bring all this up because during my time playing the totally evil elves, I actually thought to myself, "this seems a little too evil for me." I know that these naughty elves, as I like to call them, are supposed to be hedonistic, selfish, jerks. And, at some level I can barely make out the semblance of some desire to reclaim their homeland. I think those can go a long way for motivation as a person playing as a dark elf.