Havent seen anything like this on the board. Sorry if its been proposed before though, I must have missed it.
So here's the hypothetical.
Disney comes to you and says "So after the current slate of films are done (Infinity Wars, Inhumans, ect) the next chapter of the MCU is going to be told in a video game (cross platform, X-Box, PS, Wii, PC) and we want to know what you'd like to see!"
Of course, there are some restrictions and conditions.
You have to abide by MCU canon. Quicksilver is dead. The Mandarin really was a druggie actor paid for by AIM. No time travel shenanigans to fix perceived mistakes. Time travel itself is not off limits, but you can't use it to change MCU history in any way, including things like "you thought Peggy Carter was an old woman, but that's really a LMD and the real Carter has secretly been brought to the present!"
We will assume that everyone currently alive and active right now still will be after Infinity Wars, and no one will be replaced (no lady Thor, no Falcon-Cap, no one has retired, ect).
We will assume that no new characters have been introduced beyond the ones we know about (Strange, Panther, Punisher, Captain Marvel, Wasp, Iron Fist, ect). The Inhumans will only have introduced the Royal family (Bolt, Crystal, Medusa, ect, no Nuhumans or Ms. Marvel).
You can bring in any character/s without limit from the MCU; the films, television, or Netflix (we'll assume the game bypasses contractual restrictions on who can appear where), but franchises controlled by other studios are still off limits. No FF, No X-Men. You can use Spider-Man but only Parker; no supporting characters, spin-offs, or villains. No Venom, Spider-Gwen, or Aunt May.
We will pretend that everyone's contract included game appearances, so every character will be modeled from and voiced by the actor. We'll assume that this does not impact the game's budget because its already included in their contract.
This can be any kind of game; first person shooter, RPG, real time strategy, fighter, MMO, whatever floats your boat.
Now, this is what Disney wants from you.
You must introduce one new hero, whose origin will be a focus of the game (doesnt have to be the main focus). This character is going to spin into his/her own solo film after the game launches, and the origin will be referenced there, but will not re-tell that origin (think Incredible Hulk's intro). The actor/actress who will play the role in live action will also perform for the game.
You must implement one semi-major change. You can do stuff like have someone die and/or be replaced, debut a Celestial, or introduce a new setting/concept into the MCU like the Cancerverse. You cannot however, do something super huge like bring in a new Infinity Stone or reboot the entire MCU. I'll leave it up to you to decide where the line between semi-major and super huge actually is. Bottom line is; this game wont have the reach the movies do, so whatever you do cant impact the MCU so heavily that the change cant quickly and easily be consumed by the general audience the next time they walk into a theater.
You must introduce a new villain, who will be the big bad behind the game. This villain can recruit established villains, but s/he has to be the ones pulling the strings. This villain does not have to be tied to the hero you introduce, but can be if you want.
Try to keep it relatively restricted to what current gen game systems can actually do. No "My game is an open world explorer and covers every square inch of New York, Wakanda, and the Kree homeworld of Hala!" or "My game is a virtual reality simulator where you get to wear the Iron Man suit!"