Sandor and Jon Snow already "died" and I'm not sure if the directors want to pull that off again.
Jon, Danaerys and Tyrion are kind of the main characters of the series plus most people love them, so I assume they will survive, although I would be very glad to see Dany die, since currently she is the #1 irritating character in the series for me.
Sandor killed so many innocent people, cant imagine him getting off with it. Jon hung the little boy which will eventually lead to his death too, you know, social justice and stuff. I feel it.
Also the people liked Robb, Eddard, Oberyn and most Tyrells, and they all got killed and that what makes the show so I dont see too much reason not getting them killed.