I'm not as into mainstream J-pop as I was years ago so I'm very much behind the news here... but besides Idols, is there that many J-pop artists/musicians who incorporated dancing heavily into their performances?
Off the top of my head I can only think of New World Order with their unique choreography.
In my opinion, Fairies are better at dancing than MM and deserve the title the most, but among H!P groups, I think °C-ute is the best. Still, as a fan, I like watching MM the most because of the formations. They're the most interesting group to watch as far as I'm concerned.
I would honestly take Dream, Happiness, Flower, and Bright over them. And if they are still technically around, I'd most definitely take MAX over them.