On the other hand, i believe it's safe to assume that this won't extend to every soloable bosses, just to those who drop a new vanity pet.
For example, i cannot think of a way to solo Thorim without bugging the encounter. After all, it's soloable content, why haven't they nerfed it yet?
Or again, think of Azgalor in the Hyjal Past raid and his 20 seconds instakill debuff. Not to mention Reliquary of Souls.
(As of raid requirements, it is a known bug working just for MC/BWL, maybe related to the fact you get in there via an item/person. If you were to try to enter them from the "original" portal, it'd tell you you need a raid group.)