Disney has a LOT of hardware currently under construction (with much of that hardware not opening in 2017 or even 2018) and a lot of projects that will have opened right around the same time as D23. Personal opinion only, I'm doubting we see any new ride/land announcements. I'd highly anticipate panels/sections talking about all the newly opened hardware (including Pandora, ROL, Guardians of the Galaxy, Shanghai, and Iron Man [HKDL]). With ToyStory Land being the next big opening, maybe we see one of the ride vehicles for one of the two attractions as well as some new POV level concept art of the area. With Star Wars Land being huge projects on both coasts, I don't see how they don't present at least SOME new stuff about those projects... maybe talk about some of the food options or show off some of the concept art for the costuming for the area, but too soon for new details on the rides. My gut feeling is that the biggest announcement we might see would be Joe Rohde (at the end of a Pandora presentation), announcing that Everest would be going down for an extensive rehab which would see the Yeti returned to it's original intended glory. I think such an announcement would go over big at a D23 event (as opposed to the blog) and with Pandora open, this would be the time to do it.