I didn't expect an actual event until later next year. If it's this early, I guess they won't reveal that much (my money was on XVI announcement Dec 18th).
I expect an overview from all the games in the franchise, sort of like the DQ events that took place this year. Dissidia PS4 port, XII release date, XV fanservice DLC and Episode Gladio trailer.
Nomura had prepared FFVIIR info for this year before XV got delayed, so I expect a new trailer revealing Tifa and Aerith, along with the full title of the first episode and key visual. They won't reveal anything KH3 related since 2.8 releases too close from this event.
I'm morbidly curious about it. I actually love the X series but it just seems so strange that after all these years they are considering on making another game. I kinda want to see it actually happen just to see what they come up with
Keep in mind though KH3 is an entirely new game that they have to figure out. FF7R while still using all new assets already has the plot, characters, enemies, etc all layed out. I'll honestly be pretty surprised if Part 1 isn't on store shelves by early 2018