Did we or didn't we do these things?

One thing I've started to notice during my questing and during my first couple of dungeon runs since the Shattering is that Blizzard has moved the old world forward through the Cataclysm in a very inconsistent manner.

Let me explain what I mean:

Before the Cataclysm, the quest Lost But Not Forgotten by Misha Tor'kren in Durotar was about her son having gone missing. You end up finding his remains in the belly of a crocolisk, and while she is obviously very sad, she thanks you for providing her with a definite answer in regards to his fate.

In the new world she gives you a quest with the same name, but in it she acknowledges that her son has been dead for a long time and asks you for help with crafting an item in his memory. This basically acknowledges that the previous quest already happened: her son disappeared and she was informed about his death.

On the other hand however, we have quests like Fizzled, which asks you to fetch something from a character that you supposedly already killed for some guy in Razor Hill years ago. Apparently that quest did not really happen.

In the Barrens I saw the same pattern: On the one hand Mankrik is full of hatred for the quillboar because they killed his wife, alluding to the adventurers that he asked to look for her back in the day already having confirmed her fate.

Yet another character asks me to kill Kreenig Snarlsnout, another named guy that I already killed years ago. Likewise all those centaur leaders whose heads I chopped off back then are also miraculously back from the dead, pretending that the story of those quests never happened either.

Ragefire Chasm still has Oggleflint and Targaman the Hungerer, perpetually frozen in time, but the Deadmines are full of new bosses and no more Defias because we killed those and obviously things are different now.

I don't know, it doesn't make the quests any less fun to play through, but if you're trying to think even the slighest bit in-character, it's just odd. The way everything that you kill respawns after a few minutes has always required a certain suspension of disbelief, but at least I was never being asked to kill the exact same NPC twice while being told that this was actually happening five years later. Either the quests we completed in original WoW really happened and have had an impact on the world or they haven't, but acknowledging that some happened while pretending that others didn't just feels strange to me.

It's almost as if the developers couldn't quite make up their minds whether they wanted the Cataclysm to truly move the story forward or whether they just wanted to overhaul the existing quests and streamline them. I'm surprised that nobody pointed out to them how weird and inconsistent it would look if they redid some quests with the former principle in mind and some according to the latter.