My guild in 04 was rerolled to Alliance since Paladins were more powerful than Shaman and we were a PvE raiding guild. Because there were fewer players from the Horde side at the time of launch the guild was also more difficult to acquire quality Recuits. It had nothing to do with do with racial skills for PvE.
I'm not sure most players made up their minds to make a FACTION due to racial issues in vanilla. This wasn't the exact situation I experienced when I was younger. The Rank 1 friend I played with for a time decided to g