newbie
Well-Known Member
The lead has to know (more or less) what the accompaniment is going to do so the improvisations will fit.
Then it's a lower form of improvisation. More like, a variation on a given theme. It's one step towards improvisation but with still a long journey to walk. The more known-beforehand factors you add (dancing at your usual milonga with your regular partner on the same song that the same DJ always plays at the same hour), the more likely you are to lead the same dance.
Now if you like analogies with musicians, I've heard better than your lead "improvising" on a prepared tune played his orchestra. During a birthday party (our ballroom teacher's jubilee) the people who wanted to sing something were accompanied by an amateur pianist, also a pupil of our teacher's. He had no partitions (being blind) and wasn't even asking what the title of the song was. Instead, he would let the singer start alone, and once he feels the music he would start to play the piano by the ear, feeling what the singer was likely to do next (accelerate, slow down, change the tone, end) but never knowing for sure.