Outside of project by independent studios like Insomniac (R&C Movie Game) & Supermassive games (Until Dawn)...
I definitely expect:
Santa Monica - God of War
San Diego - Drawn To Death
Polyphony Digital - Gran Turismo
Naughty Dog - Uncharted
Team Japan - Unannounced Titles
Media Molecule - Tearaway Unfolded / Unannounced Project
My gut is also telling me:
Team Ico (they're too quiet... I think it's time for a teaser)
Sucker Punch - (Infamous has come and gone... time to announce a new project)
Guerrilla Games - Unannounced Project Unveiling
^^this... mixed in with your third party unveilings... makes for a good show.
All at E3? Do you guys ever learn?
1. Sony doesn't announce their games 2+ years from release anymore (unless there's a significant delay).
2. E3 does typically get the biggest announcements but Sony still tries to spread them out between E3, Gamescom, TGS and PSX.
Here's what I'd expect this year:
E3
Japan Studio - The Last Guardian
Level 5/Japan Studio - New JRPG IP #1
Quantic Dream - New IP
Guerrilla Games - Horizon
Gamescom
Sony London - Playroom VR
Media Molecule - New IP
Sony Bend - New Horror IP
TGS
Japan Studio (w/ another studio) - New JRPG IP #2
Japan Studio - Gravity Rush 2
PSX
Sony Santa Monica - God of War 4 (maybe, a teaser at best though because it's a Q1 2017 game)
Mix in games that've already been announced (U4, R&C, etc.), maybe some DLC (Bloodborne and The Order DLC, please), a couple of remasters (Uncharted Trilogy, Beyond) and a few smaller second party announcements and I think that's pretty much it.