Now that this thread is alive again, I'm going to toss out a few predictions of my own.
Bethesda
- Doom gameplay & release date
- BattleCry trailer & beta release date
- Elder Scrolls Online expansion announced w/ trailer & release window
- Dishonored II announced w/ trailer
- New IP teaser trailer from Arkane's second team
- Fallout 4 announced w/ gameplay & release date
Microsoft
- Exclusive & timed content on Xbox for Battlefront, Rainbow Six, and some others
- Forza Motorsport 6 trailer & release date
- Quantum Break gameplay & release date
- Battletoads announced w/ trailer & release date
- Killer Instinct Season 3 announced w/ trailer & release window
- New IP from Twisted Pixel announced w/ trailer & release window
- Exclusive and timed indie game montage
- Rise of the Tomb Raider gameplay & release date
- Halo 5 campaign & multiplayer gameplay & release date
- Scalebound gameplay & release window
- Crackdown trailer & release window
- Dino Crisis reboot announced from Capcom Vancouver (Dead Rising 3) w/ trailer
- Banjo Kazooie 3 announced w/ teaser trailer
- Gears of War 4 announced w/ teaser trailer
EA
- Star Wars Battlefront gameplay & release date
- Mirror's Edge trailer
- Need for Speed announced w/ trailer & release date
- Gameplay/trailers for this year's sports line-up & release dates
- Criterion's New IP announced w/ trailer
- Mass Effect 4 announced w/ trailer
Ubisoft
- The Division gameplay & release window
- Assassin's Creed: Victory gameplay & release date
- Rainbow Six: Siege gameplay & release date
- UbiArt engine Prince of Persia announced w/ trailer & release window
- New IP from the Child of Light team announced w/ trailer & release window
- Just Dance 2016 announced w/ trailer & release date
- New Splinter Cell announced w/ gameplay
Sony
- Ratchet & Clank PS4 gameplay & release date
- Uncharted 4 gameplay & release date
- New IP from Sony Bend announced w/ gameplay & release date
- Sony Third Party Relations segment w/ localization & indie port announcements
- Exclusive and timed exclusive indie game montage
- Montage of upcoming Sony collaborations (Edith Finch, Wattam, Drawn to Death, etc.)
- PS1 Classics announced for PS4
- Morpheus information w/ demo footage and list of games/publishers that will support it
- Gran Turismo 7 announced w/ trailer & release window alongside Morpheus
- New IP from Level-5 announced w/ trailer
- Trailers/footage of Final Fantasy XV, Metal Gear Solid V, Street Fight V, etc.
- Destiny major expansion announced w/ trailer & release date
- New IP from Guerrilla Games (Horizon) announced w/ trailer & release window