Not even a little convinced that either mode would bring back any significant number of players.
Am completely convinced that the sbmm in this game is already horrific and adding more modes would only make the problem worse.
You know what? Now that I think about it I don't really believe that it could get any worse. That's how bad it already is. So sure. Why not? Add more modes if that's what people want. If it brings longer queue times that's not the end of the world, and if the sbmm gets worse I doubt very much anyone would even notice.