I feel the need to put my two cents in on this topic. First of all, I don't think there is a need to worry about Taylor Swift going all Miley Circus on us. Swift has talent and she knows it. Cyrus doesn't really have talent and she knows it, too. In order for Miley to continue to have a career, she will have to turn into a clown. Swift won't have to do that.
As far as Swift's songwriting, my first comment is that I am not into her music, but I believe that she does write her own songs. Those songs first topped the charts in the Country genre, so she conquered that portion of the music business at a very young age. Then, in a brilliant career move, she changed her brand to become a pop star, and she is now conquering that part of the business as well. Just amazing if you ask me. So, while some may not like her lyrics, they are pretty effective at reaching a wide swath of fanbase. Maybe more than anyone we have seen since Michael Jackson in the 80's?
As far as her looks, she is the type of girl that looks really good now. But I predict that she will look absolutely outstanding when she gets to her late 30s and early 40's.