When the Alliance wins a battleground, you can be sure that somebody attributes it to them having paladins. In the other direction, if the Horde wins, it's just because of shamans. Well, bad losers will have to think of a new excuse soon. VGGEN.com News reports that in the Burning Crusade expansion set, the Alliance will have access to shamans, and the Horde to paladins, both via the new races.
From a point of game balance, that is nice. From a point of storyline, it erases one of the last differences between Horde and Alliance. Playing Alliance now I already sometimes have the problem that I forget that I'm Alliance and run to the Horde windrider master in a neutral town. Once you left the newbie zones, which are different from each race, the differences between races are so small, they become insignificant. When Edward Castronova claimed on Terranova that the Horde is evil, and playing an evil avatar was an expression of personal evil of the person playing Horde, most players strongly disagreed. You choose Horde because you haven't done the Horde quests before, or because you like the look of the orc's wolf mount. But when actually playing that orc shaman, he is exactly as good or as evil as your human paladin would be. Might as well be able to play a Horde paladin.