Realistically, speaking though... what can we expect?
The 'big global Japanese devs' have already showed their cards at E3 or previous showings. (MGSV, FFXV, KH, Deep Down, etc)
The other 'franchises' that has the popularity and star-power to be in next-gen have already been 'exclusified' by Nintendo. ( Sonic, Monster Hunter )
Japan Studio (both 3rd party collaboration + internal teams) is already on track to be releasing 5 games this year, which is already quite a lot. At most, they have only 2 or 3 teams that is potentially working on PS4 titles. ( one being Team ICO and the other Team Siren )
I think I echo everyone's sentiment when I say expectations on 3rd-party developers to be on the forefront of next-gen is...extremely low. (mobilemobilemobilemobilemobilemobile)
Aside from a few devs, and Sony possibly funding/publishing for some 3rd-party titles, I just can't imagine a wow showing from anyone at TGS.
I hope he'll be there, I wanna hear him speak Japanese.