Also, and i dont know if its still in effect, they have that rule where they wont show a game that is more than a year away from release, or something like that.
TBF Sony showing off games years off helped them build a lot of momentum with PS4. I got super-hyped on Dreams but little did I know it'd be SEVEN YEARS before it finally came out xD.
I think if it's a game MS knows only they are bringing, for this early phase of next-gen it's perfectly fine to show a few games that might be a few years off. Simple teases, etc. Sony already had a couple games in their show that are 2022 (think it was 3rd-party though), so MS showing 1 or 2 games that are 2022/2023 as small teases to build that early hype would do them very well, especially if they're visually showstopping.
Bonus points if they're strong on nostalgia
If you have it, show it. I used to think people show games way too early...and they do...but apparently nobody else seems to care. Sony shows first party games way early, microsoft needs to just show everything no matter how far it is in development. Just knowing a game exists (FABLE) can help someone who is on the fence
Exactly. People underestimate HOW MUCH showing games years off helped Sony build strong momentum in PS4's early years. Dreams, Uncharted 4, SFV, Shenmue 3, FFVII Remake etc. All shown at least two years before release (some even earlier than that). Can extend to stuff like Crash remakes, too.
A lot of people like being sold on a vision for the next-gen and if that means showing off a few games that'll be years away, so be it. I don't think MS needs to go overboard (and certainly avoid some of the mistakes Sony made in this regard, like with Dreams, which turns out was just shown WAY too early), but 1 or 2 2022/2023 1st-party teases would be amazing especially if they're for IP with established fanbases.
They don't even need to be 1st party, tbh. 3rd-party platform exclusives would do the job as well, just as long as they impress and make a statement, and get people anticipating to know more (they also need to clearly communicate they're console-exclusive to Xbox as well, that's something they didn't do too well with the May showing of games like The Medium and Scorn).