World of warcraft 4.1 stuck on a decision?

Hey, ive just came to playing world of warcraft again. I had quit in wotlk with a level 80 death knight. Know that ive come back i dont know to much since cata has come. I heard in 4.2 dks are getting nerfed and will be useless... Should i continue leveling him to 85? and gear him up? Or should i start on a new class to get up to 85? Please Help. Ive been thinking about a rogue, druid, or hunter.