Oh and about Kelly being basic or that her music is all the same:
I was thinking about it lately and I think that Kelly's music might sounds all the same because you can see similarities in her big hits. Excluding A Moment Like This, Because of You, Already Gone and Mr. Know It All and maybe Breakaway (again, only the big hits!), all the other hit singles are more or less pop or pop rock uptempo anthems with huge choruses. Of course they moved musically a bit, from a little RnB MI to pure pop rock SUBG and BTHE to more rock sounding NA to bubblegum MLWSWY to more dance oriented Stronger and electro sounding CMB but the base is still here. The themes of the songs are similar too - most of them are either break-up or empowerement. As GP hear probably only these big hits, they assume that Kelly's music's all the same.
We, as we're familiar with Kelly's complete discography, know that her music is much more diverse than it seems to be. Just as Kevin said, we have soul/r&b Thankful, pop rock Breakaway, rock and alternative My December...
To be honest, I think that the "music's all the same" thing can be applied on almost any of the pop gurls. In my opinion, as I know mostly only the singles or just few songs, most of Katy's or Beyoncé's songs sound identical to the rest of their songs. I also think that Pink's last 3 albums (I'm Not Dead, Funhouse, TTAL + GH singles) are just repeating the same formula. And the list goes on. However, the Cats, Hive or Pink's stans would call me stupid and deaf because their faves' music has evolved so much in their opinion. They see the progress, just as we see the changes in Kelly's discography.
I think the key to this mystery is: How much are you familiar with the artist's discography and how much attention do you pay to it? Just my opinion though.
