I've been thinking on King's Rolling Death Cradle (RDC) vs King's Screwdriver in terms of usefulness, instead of sheer damage.
What's good about RDC:
One of the things is that it's easily incorporated into King's "wavedash" meaning more variety, meaning more pressure.(By the way, King's "wavedash" has 3~5 different options, one being the rising knee move, which pretty much allows for a throw (giant swing preferably, for fear effect) after, Black Bomb, for crouching opponents who think you are going for rising knee or the Death Cradle, and maybe some other stuff I don't remember at the moment/not that useful.)
The only problem RDC kinda has, is that it's a 3 sequence throw combo.
"Problem", mostly because mashers tend to escape it more easily than Screwdriver.
If finished successfully though, damage is kinda similar to Screwdriver, and it pretty much grants the "fear effect" of the wavedashing.
That was my latest test.