So, would it use our pets we have on hand or would it be more like the group of npc's we get when you do the Firelands daily at Sethria's Roost? Just some random animals.
Would it use any of our pet's special abilities?
We're talking about something that is completely hypothetical, so anything is possible.
I personally would want the ability to call the five pets that I actually have on hand at the time, since that would give me control over what everyone sees when I send out the stampede.
Furthermore, it makes a lot of sense for the spell effects to not vary much from hunter to hunter, so special abilities would be right out, *but* I wouldn't mind seeing the pets going through their best motions.