Environment paintings needs selections like foreground, middle ground, back ground and minor selections. To control easier this divisions, automatic selections could be handy. E.g: 1-Define fg, mg, bg ideally with 3 selections. 2-Put each of these layer masks in a group 3-depending where we paint, krita switches automatically to the right selection which we defined previously. Fg, Mg, Bg cannot share the same area else things don't work.
Hmm, alright, that needs: - discussions - behavioral mockups (how exactly it behaves, how to turn it on and off, how to define those selections, how to show it in the layer stack or in other place), maybe even GUI mockups
Does Layers + masks + (Kayboard shortcut)[R] to change to layer under paint not achieve the same result, or similar? For what I see the only missing step in your workflow is pressing the R shortcut before painting, so long there is paint in the area you are about to paint.