Here's my thoughts:
Katy Perry is not meant ot do trashy dance music and wear edgy costumes like Gaga or Nicki Minaj. I think if her albums start heading towards a rock sensibility, it will give her more longevity and show that she isn't nearly as annoying. Her music isn't anything new (though I adore Firework and The One That Got Away) and it always seems like she's trying too hard to be popular. If she takes a break and tries making more mature music, she'll be more of a critical success.
Everyone nowadays is trying to be like Lady Gaga: Nicki Minaj, Christina Aguilera, Katy, Rihanna, even Beyonce. Britney is edgy without being bizarre, and Christin and Beyonce still can do very classy stuff. It works for Gaga because it's her style and it works for Nicki because her music is also nucking futs. Christina tried hard to do he edgy/future thing with "Bionic," and look what happened. If these artists try to be more like themselves and not worry about spectacle, it might help them in the long run.
Of course, this will never happen. Nor will my Lady Gaga standards, Beyonce smooth jazz, and Britney Spears rock and blues albums.
/rant
"I saw Pavarotti play Rodolfo on stage and with his girth I thought he was about to eat the whole table at the Cafe Momus." - Dollypop