It's one of those things I really hope will change before the expansion goes live. It's a waste of good potential of horde paladin, unless Blizzard has something planned down the road (though so far, speculation goes that next allied races are Dreanor Orcs and Vulpera, so I doubt any of them end up having paladins).
It will probably mean Dark Iron dwarfs wont have access to shamans, which would suck as well.