I 3 manned BWL in MoP with a full naxx priest and rogue(i was a full gemmed pvp prot war) and it was simple with the 15k shield slams, i came back recently maybe mid WoD and tried the same exact thing with the same exact group and gear and could not, they really brought back the challenge in the old raids forsureI will say, I've done BWL with 3-4 people pretty easily numerous times. But we're talking full t3 Naxx geared characters with the Naxx and ZG enchants, etc. Doing it with gear from MC and BWL is an entirely different ballgame. Also, when I did this last...I was a Full T3 Prot Warrior when Prot was insane and getting 15k shield slams.
So I can see why people will say it's doable with few.
Not every class does, and survivability is lower for many.Cause its not logical, u do more dmg now than u did in mop, and bosses have equal hp, u cant 3 man it. It explains itself.