Her touring. If she can't sell albums, she might as well rack up some coins with tours but her last one didn't do so hot, so I'm scared to see how things will go with her next tour.
Other than that, then obviously my next fear would be how her albums perform. I don't really care so much about singles, mostly albums.
Rihanna - Getting beaten by Chris again.
Katy - Getting pregnant by John.
Miley - Retiring.
Nicki - Her next album is too Urban without any appeal to Pop.
Death @ some of you talking about success/flopping.
Britney: Another breakdown... if she has another one I dont think she will handle it
Wynter Gordon: to stop doing what she truly loves, in this case, music, because of not being sucessful. Gurl, don't give up.
September/Petra Marklund: if she does yet another extreme change in her music. Is hard to still stan for her that way.
Kylie Minogue: another cancer :\
If she can't sell albums, she might as well rack up some coins with tours but her last one didn't do so hot, so I'm scared to see how things will go with her next tour. 
Let me knock on wood.
