Idea is a stance for all characters in wow to either stand , crouch or prone while moving.
Let me guess, you also want the ability to first person, and if you hit something in first person, it automatically crits?
wrong guess. also, using attacks while mounted would be KEY. You can already do it from the ducks in the WPvP zone Oshara Plains. just anther thing locked behind an unnessicary gate. why? I would appreciate an answer, and preferably not a sarcastic one either.
We can’t answer these questions bro. 
probably not built into the engine… and no demonstrable ROI to implement.