The fires out in BEM aren’t bad and they’re a lower level as well than the ones in Elemental Plateau, but I still go to Elemental Plateau to farm simply because it is closer to fly to, haha. After doing all the dailies though (starting with Skettis and then going to BEM) I think I may go farm the fires out in BEM if not a lot of people are there. Primal Water are extremely easy to farm for a Warlock as well though, so I do that on occasion as well.
Primal Fire is easy as *edited* for a mage to farm though, especially in BEM 