Haha, I mean, have you seen the game though? The focus on idols in all their forms is leagues beyond any samurai references in SMT4. They went IN and that's why you see so many who were turned off.
I do think they went for something that was really trying to double down on the otaku teenage anime audience. We even have 30 year old doughnut loving Naruto in the game.
That said I think it's still something more similar to Tokyo Xanadu, TWEWY, or Persona than an actual rhythm game. However, that audience isn't always huge, is not tremendously easy to cater to, and is not what I'd immediately associate with the Wii U.
Going back to the Splatoon comparisons I did earlier, that is also a game about embracing youth culture, but it tries to do it on a more abstracted level and put in elements from around the world instead of going 100% in on the more intense parts of Akihabara culture.