Like Tauren Paladins, or Gnome warriors, etc...? yeah, they are a bit "forced", but like we all saw, Blizzard don't have nay problem expanding the gameplay with some excuses, quest-texts, or using all material/story-lines (wildhammer clan/ highborne n.elfs / etc...).
The only problem that I have is that your character should be "deformed" with the main characteristics of the story-faction (tatoos for wildhammer clan shamans, eredar faction for warlock Draeneis, white/silver hair for Mage N.Elfs, Green or black skin for Orc Warlocks, etc...).
Blizzard already said that this features are in their wish-list too. But a "wish-list" is really far from "what the game needs".