I respecced BM a couple days ago to get to 70 faster. At the time, I was certain that I'd use it to race up to 70, then undoubtedly want to go back to Surv.
If there is one thing, however...and only one thing...that could conceivably convince me to stay with Beast Mastery, (it actually isn't Bestial Wrath, or Serpent Swiftness) it is Intimidation.
A real, controllable, truly viable Taunt is something I've wanted for my pet for pretty much the entire time I've been playing with a Hunter. It lets me keep FD as a backup...so I have a second option in emergencies.
It just might sway me.