And no one seems to remember Blackwing Lair, the Raid that recieved *no* testing and was released so that it would be a "Surprise" for the Raiders, and it was a complete and total broken mess.
Or C'Thun and his belly tentacles. Or Yogg-"It's mathematically impossible"-saron. Or Arthas and his Saronite Bomb shenanigans.
And those are just the ones that are coming off at the top of my head. I'm sure there were plenty others back in the day I simply can't remember. This sort of thing has *always* been a thing with end-bosses in Raids, because Blizzard doesn't want to test them externally due to the stupid World First bullshit. You can either have a boss that is tested well and remains challenging, or shit like in XIV that are tested internally, but are so scripted and undertuned you're basically playing DDR and can complete the raid with the previous tier's gear.
As for the people crying that the boss has too much health and is over-tuned: Why is that a bad thing? Heaven forbid the boss doesn't die in a single reset or two. Weren't people constantly going on that end-bosses die too quickly now, and they should last as long as they did "back in the good 'ole days"?
I swear, sometimes you guys really do capture the whole "Wanting your cake and eating it too" metaphor.