I guess our ideas of "blocks" are different. There is no way to achieve this with Voronoi stretched from my end, whether a small stretch or long stretch, and again, if your cliff isn't a sheer 90 degree angle you'll just end up with voronoi angles/ends (those points you mentioned). and deep lines on X and Z; ribbons. '
You can use lowest cut away for some block like features, but again, they don't work well on Y due to cliff angle, still get the deep channels that end to hard which can create weird inverted creases if not careful. You'd have better luck with infinite X and Z or Y merged lines, like the square noise function.
This preview is on X and Z though, which looks nice in illusion, but as soon as you go lateral, you got basic voronoi shapes mixed in with blocks on X lol