The only differences are race, population, and paladin/shaman (for classic) basically nothing else makes a horde player different from WOW TBC Classic Gold an alliance player. PVP is more popular among players who would rather join the meta faction (horde). However this is just minor in comparison to the huge population imbalance and the problems it causes. My guild in 04 was rerolled to Alliance because Paladins were superior to Shaman and we were being a PvE raiding guild. It was also more difficult to cheap Burning Crusade Classic Gold find good recuits since there were fewer players on the horde side at launch by a large margin. It was nothing to do with racial PvE skills.