I'm going to wager no. In Blizzard's own predictions, it will make Fire stronger, but not quite to Arcane level (even post-nerf). But it will probably be close enough that either is viable. Or not, who knows.
One thing that scares me a LOT right now, is that Blizzard has a big beef with Torment the Weak. Now, I get WHY they hate it. I mean, realistically, it is a 12% damage buff in any raid context (and most groups). And that sucks, because it's a single talent responsible for a hell of a lot of damage (and it's low in the tree).
But the problem is that it is also part of the balance. If they were to get rid of it, Mage DpS would drop 12%. That's just how it goes. But, because it is a passive bonus, it is very hard to recreate elsewhere. And you can't just make the abilities themselves do 12% more, because then you are just freeing up 3 points for Mages to do MORE.
The other problem is that they want every class to have "interesting" talents. Like if snares weren't so constant, the mage would SOMETIMES have 12% more damage.
But the only way to do that without heavily nerfing Mages is to make it a chance thing with a huge bonus. But then that isn't any better, because you just open up the RNG to occasionally do massive damage. Which can mean the Mage rips the meters to shreds or barely places sometimes. That makes them a higher-risk unit.
And one CHANCE talent meaning 12% of your DpS sucks. It's why I hate Frost right now. And Blizzard doesn't want it either, because that would just make it the mage Eclipse, which is another talent they don't like.
Blizz wrote:
Because it's so overbudget, it can't be situational or mage dps swings enormously. Eclipse is in a similar boat. It's not a bad talent per se (in our minds - druids may disagree), but because the swing is so large, any time you don't benefit from it, your dps drops a ton.
This. That's a problem. The best thing I can imagine is to have it give a small passive buff to damage and have a proc associated with it, that has an ICD, but a decently high proc rate, that does SOMETHING interesting. Hell, I don't care if that "interesting" is that it summons a mirror image to fight for you. Of course, if that procs Mage T10, it would be an extremely strong talent...
Summary- Blizz makes bad decisions, and then chooses not to fix their bad decisions when it would be easy to do so, which then pisses off people later.