Swapsets could/should be done in a single layer, similar to the way Visemes are done, if they are included in the same parent object. For instance: if I have a series of shoes for the right foot (pointing inside, middle, and/or outside) that change angles depending on the motion of the puppet, I should be able to slice a single item on the timeline and change said shoe. This will be more efficient, better organized, and give us better control of more advanced animations.
The image below could be well organized in two layers rather than 6, and it's only going to grow as I finish this fairly short animation.

