I used the world first clears as an example because that's how you evaluate the difficulty of a content. When Gordias was cleared by Elysium after around 1 month, most of the playerbase couldn't clear it even several months afterwards.
Because if the world first players took that long, then the more casual playerbase wouldn't have a chance of clearing it before the next raid tier came out.
On the other hand, if the world first is claimed only 12 hours after the tier release, like what happened with Eden, that means the tier is going to be very easily approachable even by the casual playerbase, especially after they get more gear.
That's because the DPS checks have become a joke nowadays, and you can clear most fights on the first week even with multiple deaths.
This wasn't the case in Gordias and this wouldn't be the case if the bosses had more HP. If Titan had had its HP buffed by 15% or even just 10%, I'm sure nobody would have cleared the first week, and maybe even the second.
Yet, if the tuning is so lenient, you're going to see clears very early on because you can just ignore mechanics and healer LB3 for example, to get through them.
They would, but they would definitely not take just one day to clear.
The CD resets only affected the time you had to wait between pulls when you finally reached enrage, because before that you would chain-pull regardless since DPS was not the concern before reaching the end of the fight.
And defensive CDs like Hallowed could just be swapped around if they weren't ready yet.
The DPS checks and healing checks were harder, mechanics were more punishing and insta-wipe most of the time, like with bosses getting damage up stacks if you failed them.
That's still more than a week longer than what Savage clears take today, which is one day or two at most. And I'm pretty sure WoW has been out for a bit longer than FFXIV, so people know how to play that game.