Gamespot got word that Blizzard plans cross-faction classes: Horde Paladins and Alliance Shamans.
“The Burning Crusade, Alliance players can play as Draenei shamans, while Horde players can play as Blood Elf paladins. Previously, players on either side weren’t able to access those character classes; paladins were exclusive to the Alliance, while shamans were exclusive to the Horde. According to Blizzard, Horde paladins and Alliance shamans will have many of the same talents of their traditional counterparts, though they “will also enjoy some unique abilities to themselves, similar to the priest class’ racial specialties.” Since this new feature will fundamentally change the asymmetry between the game’s two factions, it will presumably have a significant impact on the way the game is played, especially in competitive player-versus-player combat.”
Blizzard site now has a new preview:
As we draw closer to the release of World of Warcraft: The Burning Crusade, more of the secrets shrouding the draenei and blood elves are being revealed. In the upcoming expansion, you will finally be able to play classes that were previously unavailable to your faction. The blood elves have harnessed the power of the Light for their own needs, and the Horde recognizes the value of these renegade blood elf paladins. Meanwhile, the draenei have been granted the wisdom and strength of the elements, and a number of draenei now follow the path of the shaman.