It's obvious what is happening. I will list my predictions regarding each studio attending the event.*
Sony Santa Monica = God of War 4 Teaser / God of War Remastered Collection
Naughty Dog = Savage Starlight Teaser + Uncharted Collection / Uncharted 4 Gameplay
Media Molecule = Unveil of New IP
Guerrilla Games = Horizon RPG
Sucker Punch = Infamous 3
Ready at Dawn = The Order: 1886 gameplay blowout + Joining Sony WWS
Capcom = Street Fighter 5 (Exclusive)
Square Enix = Final Fantasy VII Remake (Exclusive)
Activision = Crash Bandicoot collaboration with Sony WWS
EA = Announcement of Titanfall for PS4
Warner Bros = Mortal Kombat 8 exclusive DLC for PS4 / Batman: Arkham Knight DLC also exclusive to PS4.
All DLC will be at least 1 year timed in duration, all to the delight of Xbox One fans.
Valve will unexpectedly arrive at the keynote with Gabe announcing Half-Life 3 for PS4 (Exclusive) and a sequel to Left 4 Dead.
Kojima will show up with exclusive DLC for Metal Gear Solid V and an announcement that Silent Hills is exclusive to PS4.
Crystal Dynamics will announce Fall of the Tomb Raider to appease PS4 fans - Phil Spencer will be in the audience crying into Major Nelson's shoulder, while he just grins menacingly.
Geoff Keighley will spontaneously combust with excitement while Joel Mchale will appear from the shadows and attempt to extinguish him, but will fail due to a never-ending supply of layers.
The Last Guardian will be the ''one more thing''.
Free PS4 consoles for everyone.
Age of Sony will resume, unabated until the internet, and space time continuum collapse when news from this historic events filters to the masses.
*What actually happens may differ slightly.