My earlier post mentions a problem with Plasma, wherein I was unable to add a workspace switcher to the panel, and I made it clear that it was a VM--I hadn't tried to install it on hardware yet. Now I have, and the problem's the same on a hardware machine. Damn shame, because I was really enjoying Plasma, and was ready to change my development machine from Budgie to Plasma, at least until I found some reason to return to Budgie.
I didn't realize I'd find that reason this quickly.