Of the three Warlock specializations, Affliction has never really appealed to me because it seems the most wholeheartedly, unabashedly evil of the three. For a time, my Warlock was Demonology; I imagined her as a wildlife biologist who was interested in studying the biology of demons and got even more thoroughly swallowed up in her chosen field than most academics do. Then the Metamorphosis mechanic was introduced, and although the Demonology-only wild imp swarm that was introduced at the same time did appeal to me a great deal, my Warlock didn’t want to transform into a demon herself, just study and control them. I changed my Warlock’s spec to Destruction and re-imagined her as a Fire Mage corrupted by her lust for power. Datamining from the Warlords alpha client has revealed a new glyph that changes the Metamorphosis effect to cause the Warlock’s normal form to sprout demon wings instead of undergoing the full transformation — suddenly, Demonology is much more attractive to my Warlock again! She promptly ran out to her trainer to pick up Demonology as her second spec, though she won’t be using it until after Warlords actually launches. As for her backstory — Sin’dorei live long enough that she could have been both a crazy fire mage and a crazy wildlife biologist at different times in her past.
(Another glyph that I am excited about is “Play Dead”, which causes a Hunter’s pet to feign death when the Hunter does — something I’ve wished my Hunter pets could do for a long time!)