Originally Posted by
Chemii
A quote with a list, wherby the OP states a boss took five hours to kill was the 3rd hardest is not really convincing.
When Paragon released their statement after killing Lich King Heroic, they said about how hard it was, they made note of the fact that it was harder than anything they've done prior to that including anything in Naxx 60. That was tier 10. In tier 11, they said again it was the most brutal to date. Firelands, Ragnaros again, something like 320 guilds killed it before the next tier.
Everyone talks up how hard Vanilla Naxx was but it was superficial, based on organisation, not actual skill. Gear checks don't equal skill, they are artificial ways of slowing down content.