The thread seems like a legitimate attempt to procure useful information. What actually seems like the derailing problem is people typing opinions to the effect of "play what you want / feel like" when that's clearly not where the op's intentions are.
It's honestly laughable that people (not you Afflik btw, I'm on a tangent) even waste time typing responses to the effect of "so what if you do less dps than the best, just enjoy what you play".
In regard to the op question, you've probably already been given the best answer you'll find. Start out as fire and see what you get as your first two (all the while, praying to rngcifer that you don't get norgannon's or the blink chest and screw your luck for all 3 specs). If you get bracers, plus belt or hat, you could probably just stay fire and focus on that. If not, switch to frost.
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Sephuz is outstanding for the fight, the best, since you can reliably proc it on adds.
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Something I thought of to add is that if you do get shit on by rng and Norgannon's plus the blink chest end up being your first two, it's a significant time saver to forget about that character for the rest of this xpac and just level up a new mage.