They don't need to wait for the next book. They can release a Wildlings vs Night's Watch now with a double sided winter board/Wall with Castle Black and gate tiles. Then give The Others as an expansion to it when "Winds of Winter" novel finally comes out.
I wonder if this game is making any money for FFG, if not it's pretty understandable why they've halted support. And of course the game doesn't have the title "Game of Thrones" on it to appeal to the casual gamers/tv viewers. They really need to put on their boxes "Based on GRRM's series ASOIAF including 'A Game of Thrones'". That's what I would do if I'm marketing, using full titles not acronyms. How many casual fans from the novel and tv know that the continent/country is named Westeros?