I'll just throw this wild idea into the ring. Maybe I'm the only one who likes it, maybe the idea will evolve. Here it comes: As soon as a program window is open, plasmoids have no more use, because they are hidden. I would find it handy if there would be floating plasmoids that are visible as soon as the overlying window is inactive. Of course, this assumes that you have several windows open. I could imagine the picture frame as a floating plasmoid. Another scenario would be to make the floating permanent. For example you could place the clock visible in the foreground when the browser is fullscreen (F11). Translated with www.DeepL.com/Translator (free version)
You can do this if you use the keyboard shortcut "Meta + Mouse Click" to move the applet window while it's pinned.
I'm talking about an interaction between inactive windows and plasmoids. Moving the window isn't part of the idea.
Interesting idea, but I don't see us doing this beyond what's already available. Having plasmoids unpredictably overlaying window contents would be really weird and confusing for most users, I think.
Fair enough. Just an idea.