i thought of an idea
what about
a selection cube that replaces deletion cube
a...
selection deletion cube
yes
How about a deletion cube that deletes an exact cube in the bricks selected, and it can do that by deleting the bricks and replacing any gaps with smaller bricks.
I hope I explained it right, basically if you cut a chunk into a 1x1x16 brick it would split somewhere into to two bricks of different sizes.