Forget about what I expect. Here is what I want. This is mostly copy/pasted from another thread but I've edited the list slightly.
1) E3 starts with Scorpio reveal. Priced at $399. Designed to look like Xbox One S, but slightly bigger. Sleek, runs cool, with internal power supply, 6.5TF, Zen processor. November 2017 release date.
*Microsoft confirms that all Xbox One games will run on Scorpio, and any game that has dynamic resolution or dynamic frame rate will automatically receive modest bumps. I.E. if Witcher 3 dips from 30fps to 25fps occasionally on Xbox One, it will no longer do so on Scorpio. If Halo 5 dips from 1080p to 720p occasionally on Xbox One, it will no longer do so on Scorpio.
*Microsoft also announces that just like PS4 Pro, games can have Scorpio patches for vastly improved performance, which includes downsampled 1080p for owners of normal HDTVs, and 1440p/4K resolution for other games. Multiple options (such as 1440p/60fps and 4k/30fps) will be available, just like PS4 Pro.
*All 360 BC games will also be BC on Scorpio. And they will run better on Scorpio.
2) Atlus CEO comes on and says "We are pleased to announced we've been purchased by Microsoft".
*Persona 5 not cancelled for PS3 or PS4 (because Microsoft is such a good guy).
*Persona 5 port announced for Xbox One.
*Persona 4 Golden remastered announced for Xbox One.
*Atlus announces they are also working on a brand new JRPG IP (exclusive to Xbox).
3) Microsoft announces they have bought Thekla (Jonathon Blow studio) and Playdead (Inside and Limbo devs) to join 1st-party stable.
*The Witness and Inside are announced to have standalone disc releases.
*Thekla and Playdead are both working on new exclusive puzzle-game IPs for Xbox.
*Braid is announced as BC on 360, and Braid Remastered is available for download at E3 (at a cost of $4.99 for anyone who owns the 360 version) with a new 1000 gamerscore.
4) Microsoft announces the creation of a new JRPG 1st-party dev based in Osaka, called Microsoft Osaka Studios.
*The studio is comprised primarily of former devs that made Blue Dragon and Lost Odyssey
*Their first game is an original JRPG IP.
5) Bonnie Ross from 343 comes on stage with the head of Rare.
*They announce that 343 Studios is working on Perfect Dark 3, developed 100% by 343 with some key Rare employees providing input
*343 announces that half their team is hard at work on Perfect Dark 3, with the other half spending significant resources to fix Master Chief Collection
6) Bonnie Ross stays on stage but the heads of Rare leave, replaced by the heads of Bioware
*They announce a Halo WRPG similar to Mass Effect 1. Developed by Bioware with input from key 343 members. You play exclusively as a female Spartan.
*The game will take place during the original Halo 1, 2, and 3 trilogy.
*You visit Halo rings, Earth, different human colonies, and various Covenant planets. No Prometheans.
7) Then Bonnie + Bioware guys leave, and Rare heads come back on stage with Playtonic Devs
*First, Rare shows off a new Sea of Thieves trailer, and they confirm the game is coming out September 2017. They confirm the game is not an MMO, not free-to-play, can be playable fully single player, and will have a massive campaign with dungeons and side quests, just like Wind Waker.
*They also show a Yooka-Laylee trailer (and at the end of the trailer it says coming out October 2017 on PC, Xbox One, PS4, and Switch) because Microsoft is such a good guy and won't obfuscate the details of any third-party partnerships.
*After the Yooka-Laylee trailer, we hear a banjo tune and the familiar banjo guffaw. Then a Banjo Kazooie 3 trailer shows. Co-developed by Playtonic and Rare
8) Sam Lake from Remedy comes on stage with Phil Spencer. Microsoft announces they've purchased Remedy.
*Quantum Break story expansion DLC is announced. You play exclusively as Beth Wilder.
*$30. Can be purchased standalone. Has its own 1000 gamerscore. Can be launched within Quantum Break.
*They also announce Alan Wake 1 Remastered, with 2000 gamerscore. Has all DLC and American Nightmare.
9) The Coalition come on stage with Rod Fergusson
*Public apology from Rod Fergusson re: microtransactions in Gears 4. The cost of microtransactions is dramatically reduced.
*Confirmed that game has been changed so that the possibility of duplicate skins/characters is now ZERO.
*Currency drops for normal game play dramatically improved.
*New story DLC announced where you play as Kait and JD. Kait is the default player one character. Takes place shortly after the end of Gears 4. Titled "Kait's Epilogue". $20.
10) Microsoft announce they have purchased Twisted Pixel and they are working on Splosion Man 2.
11) Microsoft announces there will be no Forza in the year 2017. Instead, the Turn10 and Playground teams are hard at work on Scorpio patches for Forza Motorsport 5 and 6, and Forza Horizon 2, 3, and Fast/Furious.
12) Cuphead has a trailer and release date (July 2017). It wins game of the show. Platforming levels are dramatically improved. The Cuphead dev (Studio MDHR) announces they have been purchased by Microsoft and will join the company as a 1st-party developer.
13) Phil Fish comes on stage with Phil Spencer, and they announce the creation of a new 1st-party studio, headed by Phil Fish. Will have same name as Phil Fish's old dev: Polytron Corporation
*Fez announced BC on XB1, and a Fez Xbox One port is announced. Just like with Braid, it has 1000 gamerscore and can be purchased for a reduced price if you own the 360 game.
*Phil Fish announces he is working on a new puzzle game IP exclusive to Xbox One.
14) The Fullbright Company comes on stage and announces they have been purchased by Microsoft and will join the company as a 1st-party developer.
*They spend 2 minutes on stage talking about the success Gone Home has had
*They show a trailer for Tacoma and announce it will be available later that month, June 2017
*They also announce they are working on a new exclusive first-person puzzle game IP for Xbox One.
15) Insomniac comes on stage with Phil Spencer to announce Sunset Overdrive 2
*Projected release date of Holiday 2018
*Insomniac remains third-party developer and will retain ownership of Sunset Overdrive IP.
*Sunset Overdrive 2 will be console exclusive to Xbox One, play Anywhere with Xbox One and Windows 10, but will also have a Steam release on day one.
16) Chris Charla from ID@Xbox comes on stage and announces that a truckload of previously Sony-exclusive indie games will start getting Xbox One ports
*2-minute trailer shows various indie games that will be coming out soon.
*Then the developer of The Talos Principle comes on stage and says the Xbox One port is available right now to download and purchase.
17) The head of Xbox Japan comes on stage and reveals that Microsoft has created a new fund to finance ports of Japanese games to Xbox One
*They show a trailer that shows various big games like Kingdom Hearts remasters, Final Fantasy VII, Shenmue 3, Guilty Gear, and Tales of Xillia coming soon to Xbox One.
*The trailer very conspicuously omits games like Senran Kagura and Galgun because I really don't like those games and I don't want them included in this fantasy.
18) Finally, Shannon Loftis comes on stage to show off Crackdown 3, Minecraft and State of Decay 2
*She announces Crackdown 3 and State of Decay 2 are both very close to completion and are coming out Holiday 2017
*She shows a trailer for both games.
*No mention of the cloud whatsoever for Crackdown 3. They confirm Crackdown 3 single player will be 100% playable offline.
*Minecraft 2 is announced, coming to all platforms: 360, PS3, Xbox One, Scorpio, PS4, PS4 Pro, Steam, Windows 10, Android, iOS, Switch.
19) Then, Phil Spencer says, "and one more thing". The auditorium goes dark. You hear a chainsaw and you see The Coalition's logo, and it says "The Coalition and Microsoft Studios present Shangheist". 2-minute trailer. The NY Times and Washington Post says "They did it!!! The sons of bitches actually did it!!!" on their front pages.
The list of first-party devs/games would then be:
343 Studios (working on Perfect Dark 3 and fixing Master Chief Collection)
Rare (working on Sea of Thieves and Banjo Kazooie 3)
Atlus (working on Persona 5, Persona 4 Remastered, and new JRPG IP)
Thekla (working on new puzzle game from Jonathan Blow)
Playdead (working on new puzzle game similar to Inside)
Microsoft Osaka Studios (working on new JRPG IP)
Remedy (working on Quantum Break DLC and Alan Wake Remastered)
The Coalition (working on Shangheist and Gears 4 DLC)
Twisted Pixel (working on Splosion Man 2)
Turn 10 / Playground (working on legacy Forza patches)
Mojang (working on Minecraft 2)
Studio MDHR (working on Cuphead)
Polytron Corporation (working on Fez port, new puzzle-game IP)
Fullbright Company (working on Tacoma, new first-person puzzle-game IP)
Insomniac (2nd-party) (working on Sunset Overdrive 2)
Undead Labs (2nd-party) (working on State of Decay 2)
Reagent Games (2nd-party) (working on Crackdown 3)
Bioware (2nd-party) (working on Mass Effect WRPG)