We do, though? Saronite Vapors spawning Faceless Echoes seems to be a normal event in Ulduar now. They are pretty much Yogg's version of the Sha. Probably not that bad because we didn't liter their bodies all over the land like Aman'thul did.
I didn't call that Word of God. I called that the description of the omniscient narrator (not to be confused with the characters being narrators) - because that's what it was. The omniscient narrator isn't the author, but would be the most reliable one right after the author. Additionally, it's not the player character perspective either. Our characters didn't say anything, the omniscient narrator described the it as stated in the quest text (unless you are saying that our characters have this weird habit of referring to ourselves as "you").
And no, they didn't say anything in the line of "Well, yeah, even in your theory the world would not have ended yet because, well, who signs deathwings paychecks? GUIZ WE HAVE A NEW OLD GOD TO REVEAL!". I'm not even sure if you are trying to be stubborn, or you really have problem with comprehension. They and people know that there is at least another Old God for year(s) by then. If you checked my link with a cut a few seconds earlier than the other link, the guy was already asking about the new Old God's name. If they meant to say what you said, they'd have told him "Look, you just mentioned another Old God, that's why the theory isn't applied yet". But no, they didn't. They answered that the Cataclysm was caused by the Old Gods. If they were referring to the new Old God (aka N'Zoth), they would have said Old God, not Old God
s. It's clear that they were answering the question of why we haven't seen any catastrophic event even after two Old Gods were down.
Are you actually calling Blizzard developers liars? Are you, by any chance, Rainforest? Whatever Blizzard say is the truth. That's how Word of God is - read up
on it in this article (click) in case you are clueless of what WoG means, because you are appearing so. I've said it before: it's not that whatever Blizzard say must be correct, it's that whatever they say BECOME canon / the truth when they say it until they refute it. In an exaggerated example for you to make it easier to understand: Blizzard might "lie" and tell us that Khadgar is actually Sargeras' father, and it will be canon that Khadgar is Sargeras' father. No matter how ridiculous it sounds or everything else in game up until now stated otherwise. The lore have to reshape itself to fit Word of God, not the other way around.
If you want to complain about Blizzard's devs, be my guest. Just keep in mind that regardless of what you think about those "liars", as per your words, their words are canon by default. The comics' canonical status isn't even "called into question" - they said that it IS still canon, just Me'dan being Guardian isn't. Don't state a fan's opinion you read from Wowwiki as fact, because it isn't.
Yes, the same way how tiny parasites, or micro-sized bacteria can kill humans. We did the equivalent of destroying a brain / head, and thus - died Old God.
Yeah, the same people who thought C'Thun and Yogg are still alive, apparently. One who either didn't know the lore that well, or prefer their headcanons over in-game information, out-of-game canon information, AND WoG. Sometimes both.