I stopped playing MM when they reworked it around Trial of Valor... Hated it whenever I tried it after that. I also hate the vulnerable mechanic and having to stand still for the duration of it. I'm pleased vulnerable is going away... Nothing they do to that spec can make it worse than it is currently.
As someone who has mained MM through Legion(even the opening of NH), I honestly think it does not. Most of the points why I think so have already been written up in various threads, but I understand why some other people like the changes that will be made(ie more mobility) or even those who are having a hard time timing aimed shots within the vulnerable windows while doing mechanics.
Bottom line, the vulnerable MM is my favourite MM build since Cataclysm.