I've levelled 2 groups of dual fire mages and I must say, dying was never an issue. I find it easier to run two of the same class (I have run boomkin/s-priest 1-60 as well and it wasn't nearly as much fun) and as mages, nothing gets close enough to hit you without copping a ridiculous amount of damage, and with dual sheeping and frost nova options, CC options are great. Once you glyph out evocation you even have a heal at your disposal