I will take a stab at this.
I think the wishbone would limit suspension articulation, it would bind in body roll. At what degree of body roll does it bind? I dont know off the top of my head. So that would be the main reason. It would be like ladder bar for the street, it can work but not ideal.
Second, I think watts look amazing. Here is my solution to a watts link, I have not seen this design yet.
