Another issue - one that I don't think he mentioned in the video - is that normally we could disregard all of that as "this is PTR, Blizzard will balance it". However, we have seen what happened to the Azerite system, it went live with minimal changes, required significant hotfixes early on, bandain fix with extra ring and a big rework in 8.2. Hard to be optimistic about balance when such mistakes happen within a single expansion.