I have no major problems with Nowi. Sure, I'm not a huge fan of her outfit. But I'm also not a huge fan of Donnel, Kellam, or Tharja's respective outfits. But that's not going to stop me from using them if I want.
I don't know much about Nowi. But I do know she's really really old. I can't imagine she's lived that long without seeing some pretty horrid stuff.
Where I come from, if someone's lived longer than 100 years (And can turn into a dragon) they're allowed to dress and act however they want.
Also, I hope they don't change her any. It amuses me to watch people complain about her.