I am not sure about Kristoff.
He started nine times. His best results are 9th and 10th. In 2013 he won Flanders in a great way, De Panne, Scheldeprijs and got second in Sanremo. Was super strong that year and the top favorite for Roubaix. Still he was never able to perform at his best on those cobbles. Also crashed a lot, if I remember correctly. So I can't make him a top favorite.
Politt will be very strong, I am sure about that. And he loves Roubaix, also does Dege.
I have some kind of a feeling, that Philippe Gilbert tried to duck any kind of attention before that race. He could surprise us.
It's really good and interesting, that we don't have a team or a rider like Fabian/Tommeke super strong. It's really open right now.