With Ragnaros returning in Catalcysm, along with a few other classic MC bosses, it just wouldn't feel right without Sulfuras, Hand of Ragnaros to appear in Cataclysm. It could be obtained the same way it was the first time. Eye of Sulfuras drops (Or a similarly named item) from ragnaros with a very low drop rate, and Sulfuron Hammer (Or a similarly named item) is a new craftable item. It doesn't have to be a legendary, but if it did return I want to see it be the highest raw damage weapon in the game until new tier raids come out. And, it could be a legendary anyways, just because you guys say that "it's going to be a caster weapon!" doesn't mean there's only going to be one legendary. There are supposed to be a lot more raids than there were in any other expansion, so there's room for 2 legendary weapons in the same patch. Of course, I really just want to see the Sulfuras model return, I don't care what it's called. If the model came back on a two handed mace I would roll a fucking Paladin or Warrior just because of that.
Another small off topic thing... Thunderfury (Or a similarly named more powerful version) actually has a better chance of appearing. The Skywall raid with Al'Akir with the endboss (The father of Thunderaan), Nefarian with his tinkers and engineers back with more possible elementium, Baron Geddon and Garr returning... It makes A LOT of sense. They both could return, just more updated, powerful versions.