My brother only plays fire mage I’m every expansion, he been loving it, sending me screen shots of him topping meters some fights. Always my favorite mage spec to play/watch.
That's just not true. Actual raid encounters aren't pure tunnel dps like a sim. At an absolute minimum, Fire does better than Arcane on Hodir, Mimiron, and Yogg, so even if you're a hardcore minmaxer you should have a Fire offspec. And if you aren't, Fire is still more than viable for everything else too.