Good moonkins are really hard to find in my experience. Of all the years I've raided and all the ones I've recruited, I think I've only ever raided with one who was worth a damn.
And really, any of the three specs that bring spellhaste are useful since unlike everything else that is covered by multiple specs of multiple classes, it's only three particular specs out of all 33 in the game. If you can cover it with a hunter, that's great, but then you can't use that hunter to cover anything else you're missing.