Yet, people still yearn to play vampires. It happens. And I don't actually mind people playing these type of characters in the free-form style roleplay you see in Goldshire and Silvermoon, because that tends to be the sort of place where anything goes. And I'll admit. In a former life I've LARPed a vampire.
But in troupe-style roleplay, there are usually particular character conventions. A roleplay guild focused on defending Ashenvale from the encroaching Horde, for example, would have some trouble accepting a Draenei Shaman who is actually roleplaying an apologetic ex-Eredar making amends for his crimes.
It falls on the leaders of these troupes and guilds, therefore, to talk to the person playing an outside-the-box character. You don't want to just leave your junior vampire going down a bad track, leaving him without folks with whom to roleplay. Even worse, it can lead to backbiting, disruption in the troupe, and other negative things. Roleplay groups are fragile enough -- don't leave a wingman hanging, when you can help them with the trouble.
Take a look behind the jump, and let's see how you can help bring an Edward Cullen back into Azeroth, while still making everyone as happy as possible.