There is no longer a choice between Dire Frenzy or Dire Beast, all BM Hunters will now be using Dire Frenzy for their Focus generator/Bestial Wrath reset. Well, now it’s actually called Barbed Shot instead of Dire Frenzy, and it behaves totally like a shot (in that it requires a ranged weapon, and uses a standard shot animation).
Barbed Shot seems like it’s not fully implemented at this point, but I think I can gather where it’s going to be when it’s finished. The shot you fire will now be the damage component as it applies an 8-second bleed, and this bleed is what sends your pet into the frenzy (right now it’s an instant attack and not a bleed, but I’m sure that will change). Currently on alpha, the pet still does its regular dire frenzy attacks in addition to the shot damage, but since this isn’t mentioned in the tooltip I suspect it will be removed. Your pet will still charge to your Barbed Shot target, so it still functions as a target swapping mechanic similar to Kill Command’s charge (which is nice).
Frenzy stacks on your pet are still a thing, so maintaining these stacks will remain a core mechanic. It’s too early to say how crucial it will be to maintain 3 stacks since no numbers are balanced. But if Blizzard decides to make pets do more damage again (in contrast to Legion where their auto attack damage is quite low), then a lot more emphasis could be put on those frenzy stacks.