Experimenting with steps and cloning values I soon noticed (which can be considered obvious) that fast cloning rate fills the entire level and leaves very small empty areas.
So how about roomies? Or rooms, as I tend to call them. One idea I had was actually create some rooms first, then labyrinth routine would go around them, but you could connect rooms later with a simple search routine to create a connecting piece of corridor.
Or it could be possible to extend some of the dead ends to rooms, or even search for those empty spaces and turn them into rooms.