Among the five, we can all agree that Mio was the smarter while Yui was the retarded one, right?
Then how you explain the fact that their best two songs were written by the retarded and not by Mio?
Also, though I don't like K-on! that much, I think it's a show that will be remembered by generations in a distant future. I mean, it's a fucking SoL but it's kind of different to any other out there, like if it's unique in its genre.