I found my pet getting hit by AoE fears, roots and whatnot all the bloody time which makes BM quite unreliable damage, you are literally placing half your damage in melee range. I usually find skilled players, who are often the highest priority target, to consistently hardcast 8sec cc's on my pet and I got tired of it fast.
BW, Bullheaded and Master's Call can start to feel like very limited recourses and it feels terrible not being able to use your signature ability.
MM is an all-round better option if you know how to stay out of focus and SV is especially potent in large fights (AoE roots and mass dotting)
I run BM for both random BGs and for arenas. Maybe 1/100 fights I run into issues with people keeping my pet on lock, but nothing that I cant handle. Master's call is a godsend for both BGs and Arenas, as well as another trinket. Hunter have enough CC in their arsenal to keep people on lock until their pet comes close to or completely out of a stunlock/fear/root.