I liked Renée, so I'm gonna miss her, she was the only thing I found interesting in season 5 . Her death seems so pointless and stupid (she should have seen right away because of the different clothes that it was not Sydney, she was anything but stupid), I feel that they killed her character just to shock the audience
As for Nadia, I never liked her character, she seemed pointless, and a rather pale copy of Sydney .
The very idea that Sloane, the ultimate Rambaldi freak just happened to father the passenger thus having the perfect conduit to Rambaldi was so lame ! I never could buy it, and it was a sign to me that the writers care more about the stupid plot than the characters and won't stop at any plot contrivance, no matter how stupid, or out of character
Finally, she's back 10 minutes and dies because of a frackin table ! This stupid death is just consistant with the stupid way the writers chose to develop Nadia, once again, the writers really did their best !