The thing with idol anime over shounen anime though, is that Idol anime for the most part are about this overall sense of happiness and are mostly there just for you to enjoy a group of characters interacting with each other.
No matter how bad the Idol scenes are (like LL's CG dancing), the fans of it don't care since the interactions with the girls are cute and fun enough to more than make up for it.
With shounen shows, there's always a SERIOUS overarching plot to grab the viewer, plus characters having to be set up and go on journeys, it has to nail the action otherwise those shows can easily lose the viewer. There's plot twists, character deaths, and everything else that can exhaust the viewer if it's done the same way as many other shounens, and can get easily tiring.