Like Cowabungaa mentioned, the "corrupted blood incident" was definitely one of the more interesting moments in WoW.
The reason the opening of Ahn'Qiraj was special, was the fact that Blizzard had no idea so many people would be logged on at the same time. They admitted in their 10 year anniversary video that they were not prepared. The fact that they've been caught with their pants down every launch is also interesting to note.
There was also the time where Blizzard was banning people for "wall jumping" and even talking about it on the forum. Basically you could enter undeveloped zones (Hyjal) and explore the world in a new way.
This was a vastly underrated moment in not only WoW, but gaming history as Blizzard more or less said that "it's not how you enjoy our game, it's how we want you to enjoy it". You'd think gaming journalism would've been interested in that little bit.
The 10 year anniversary Molten Core event was probably one of the best things ever. People were miserable, angry and stressed about the event and it was unbelievably funny to see "new" players trying to wrap their head around actually wiping on non-heroic (I mean mythic) content.
I don't know if Blizzard intentionally kept the fights as they were or if they thought the raid was still somehow balanced, but the end result was beautiful.
There has been many baffling things about WoW since launch, from design to customer care. People from Blizzard are hailed as rockstars (some literally), but there has come a lot of bad things out of this turbulent journey as well and I wish more people would write about those as well...
Good post, I agree. Corrupted blood is more deserving to be on the list than the arrival of the Scourge, as the latter event was basically a controlled repeat of the spontaneous corrupted blood incident.
Overall, that Molten Core event seemed like a lot of fun. But looking at the player's chat also reminded me of what is so totally wrong (in my eyes) with current day WoW. Seeing things like: "You have to be iLevel XXX to queue for raid YYY", that just makes me cringe.
I know the dungeon finder made life a lot easier in the game, but it also signifies the philosophy that Blizzard ultimately got caught in with WoW which Smilomaniac mentions: "It's not how you enjoy the game, it's how we want you to enjoy it." Things like corrupted blood and Ahn'Qiraj were not repeated because Blizzard didn't want to take any risks with their golden product, even though they had the money to do tons of interesting things.
Ultimately I feel like they're just shoving players into tiny neat little playgrounds where very little to nothing unexpected ever happens.
What made WoW great for me in the early days were the unexpected things however, the hardships you went through with other players that got guilds and lasting in-game friendships and rivalries started.
Wall-climbing was also one of those things for me and not just that but blinking or sheeping through walls, finding insane places and tricks, hidden zones. Oh goodness those days.