I know that from my own dancing, especially with certain milonga tandas, that I feel constrained not by a pre-scripted choreography but by the music. The music dances us. My wife tells me that she feels as if she is just dancing to the music and I am there with her. She's right. Mission accomplished. This feeling of the music controlling your every move in tandem is the zone where the leader/follower paradigm disappears. Sure, there are two distinct roles, but "leader/follower" is probably the worst analogy to describe the magic of Argentine tango, but perfect for ballroom tango.
Isn't this the way it's supposed to be? The music moves us; otherwise, it isn't really dancing at all, I suppose.