Nobody should ever spam moonfire. One, that's a stupid, annoying move that honestly doesn't work as well as people think, and two, you anchor their ass down with roots and use starfall, moonfire, faerie fire, swarming insects, blah blah blah. If you are resto though, yeah, you don't really have a chance. But seriously. Rogues may be sneaky, fast jerks, but you just have to remind them you are basically a mage in mail/plate that can cure poisons. Really the only classes I've had problems with are mages, due to lack of resistances, but once you get close enough, that's not really a problem. Also, treants are good friends to have in pvp.