The issue I have with most salsa parntering is that people are mainly exposed to just ballroom partnering elements, which is too limited for the amount of expressivity and flavor that the music calls for.
This is in terms of the overly-repeated basic steps, the current pattern-dancing focus, as well as the discrete or single-movement practice, where people dance with mostly hand and feet, no detailed isolations. Even when the dancers look smooth (not bouncy), their movement can still look discretized (i.e. only one or two body parts moving at a time), they are usually repetitive (no creativity), and highly irresponsive to dynamic variables (namely, the music), like in popular Swing and Hustle, due to the focus on copying popular moves.
Also these dances are "linear", they actually look good with their intended swing/jazz music. But Salsa should not be that way, should not look the same because the music is different, non-linear
And with the excessive use of patterns everyone looks pretty much the same.
This is why a lot of salsa is said to look "robotic", same thing over and over, with little nuance or on-the-fly creativity
Yeah watching swing dancers do salsa, it often looks like they're simply using salsa music as a metronome for executing swing moves