I just had my application review with WSU yesterday (I'm wait-listed, but I thought it would be good to go ahead and get it), and I received some feedback about this, so I can post it here.
I spoke with Dr. Talcott (who was super friendly, by the way!), and she told me that my personal statement was great and pretty much gave her what she would be looking for in a PS (so, not what put me on the alternate list instead of getting me accepted; moving on...).
She told me, though, if I do not get in this year and I apply again next year, I need to write a new PS. They keep our applications, so they would still have access to the old PS, and they want to read something new. Even if the theme of the new PS is the same, she said that rewriting it just helps them get to know you better (which can only help get you in, in my opinion).
Anyway, that's just WSU, but I thought an adcom opinion would be helpful.