I watched that video as well and most, if not all, of his reasoning's for placement are opinion based. Not very much fact in why he placed which healer where he did. I wouldn't believe what he says and I would just make up my own opinion by myself. See what works for you, how your play style is and what your raid comp is and go from there. Believing someone's opinions just because they are in a bigger guild does not mean they are correct. Plus, isn't Method not even going to continue in Legion??? I'm pretty sure that most of their core members left Method and started a new guild called Serenity.