Originally Posted by
Endus
This is absolutely not true, and we know this, because Blizzard tried that, and it didn't work.
In TBC, there weren't enough tanks running around, and it's no coincidence that the new hero class in WotLK was the Death Knight, with not one, but three fully capable tank specs.
And the result, to the community? No more tanks than there had been before. The lack of tanks (for 5-mans, mostly) remained a serious issue, and it wasn't until they added Call to Arms for roles on LFG that they actually made a dent in the problem.
Adding tank specs does nothing at all to the number of tanks in the game, because the one constant factor is not the number of tank specs, but the number of tank players. I have a paladin I tank on when I want to. All adding a tank spec to Shaman would do is give me greater freedom with my main. Nor would it have any significant effect on the community; the number of players who are die-hard only-ever-a-Shaman players who want to tank and can't because of that self-enforced choice is vanishingly small, and what little effect it would have would be negated by other players feeling less obligated to tank as often.
The end result? Same number of tanks. Just a wider variety.
Which is a legitimate reason, in and of itself. But if they're going to add a spec to Shaman, they may as well add a new spec to everyone.