Playing bad guys does have advantages, but its tricky.
I played in Hertzy's Council of Thieves game last year and man we wer right bastards, the entire party was neutral or below. Now minus Saif's ridiculously accurate portrayal of a evil cleric (read: serial killer, which still haunts my dreams) The group found its evil beat under the guise of power, sure we'd hurt and kill and manipulate things, but our end goal was something we thought as a positive! We were a stabilizing force on the city one of law and order (just on the totalitarian side of things) and once we consolidated everything under us things would get better for everyone.
Its like Doctor Doom he wants to rule the world not out of malice, he does it because he honestly thinks that he would be better at running it then everyone else. That mentality gave me at least (who has a hard time playing evil in video games in any fashion) sort of a guideline a carte blanc for a end justifies the means philosophy, instead of a mass murdering let the world burn villian.
Oh and as for the Hodre/Alliance it really always felt as if the Alliance were the villians to me, they come off so intolerant and that King is a straight up racist and warmonger. The Horde at least to start seemed misunderstood, seeking attonement a new leaf or a path forward. Although i think they have done away with that now with the promotion of Garrosh.

