Just to set expectations, my guess is they will keep basically everything that was there this year - Back to the Future, Dungeons and Dragons, Star Trek. Each may get tweaks/improvements based on (pretty consistent) guest feedback (changes to Trek story, more characters/scenes in BTTF to spread out crowds, better audio mixing in D&D, etc.)
I would anticipate at least one additional "major" attraction to help fill out the slate. Part of me suspects this will be an anime experience of some kind given the overwhelming reaction to this year's limited offerings.