Thanks, Michael, you nailed down what I meant perfectly. I was going to respond that "smooth" probably wasn't the right term to have used, since it has multiple facets.
I think of traditional and traditional-feeling dances as "smooth" not because the choreography is technically more flowing but because they somehow feel more lived in, as if any rough spots came naturally. They don't feel carefully engineered and crafted to be exemplars of "flow" so much as discovered, worn into shape through luck and happy use. Sort of a Velveteen Rabbit effect, if that makes any sense.