Pretty sure that beats them all.
I don't think nobody ever managed to solo the last boss of an expansion prior to the release of a new one, isn't it?
Yes, Mione does great, but it doesn't mean it feels right ;-)
This, poor blackfuse.
Main tank (DK) finishing off mythic garrosh alone...
Things like nuking down Siegecrafter in less than 1 minute.
And failing hard on paragons, only to have a tank solo the last two bugs :P