Here's the deal: all the viewers are now going to get exposed to the huge amounts of theories and ideas and lore from the books that supports those theories and ideas about where things are going.
Book readers have been keeping their mouths shut, but now with the TV show caught up, book readers are going to be able to yammer on about all the possibilities.
Anyway, very very few book readers actually think Jon Snow is dead. Also with regards to Arya: