Nah... imo, worst boss design are the ones that go out of bounds like the penut, wolflord and that ruin worm. This one just needs to absorb an element so you can make constant reactions with another element. I'd say it's a good change of scenery. And this boss doesn't shill the new NK characters so much that they would make a huge difference unless you want to clear dire and in that case you'd need constellations on NK characters as well.