Actually Valt, for me it doesn't clear anything up.

The Onyxia we can still visit now, has no place in the lore any more, technically she is dead. This is something we can ignore because of the static storyline WoW has, it is acceptable, even understandable that while some bosses die lore-wise, it is hard to make them leave the game subsequently.

But I do think that when you bring something back, like with Naxx, lore should be behind it. Because all of a sudden it is injected back into our daily storyline.

So I am having a hard time to just take your word for it that it is still the same old Onyxia, that they have buffed her, but that she only remains part of the static storyline and that there is no revamp in the lore to make up for her return. I am not saying it is impossible, not at all. Nothing is beyond Blizzard these days. I am just saying that nowhere have I seen any indication that what you say is true, and that Blizz handled it fairly decent last time when they brought back old content, so why not now?