I *know* this has been speculated on elsewhere, but I’m having trouble finding any threads dedicated to the idea.
Within the next year, provided the world doesn’t end, we’re going to have at least one Black Widow, Captain America, and possible Hawkeye counterpart in Marvel’s productions, thanks to Yelena and Taskmaster in Black Widow and USAgent in Falcon and Bucky. Feige’s confirmed all Phase 4 films thus far without an Avengers climax to it, though I believe he has confirmed they’re at least considering more projects, and if Blade is cast but not yet announced for an appearance, and the X-Men and Fantastic Four are in line to be incorporated... well, it feels like some future projects will have to be announced.
Sooo....
...Wouldn’t a Dark Avengers team be the perfect way to kickstart and change up the Marvel formula going forward, introduce new big bands, and even set the stage for the X-Men and their more persecuted story style? And I’m not even saying that Yelena, Taskmaster, and USAgent would have to be members; more that their presence shows Marvel *can* pull out counterparts if they want to.
And I think it would be excellent:
1. You want a new villain the audience can hate, but don’t yet have a Thanos-level villain to slot into place without it seeming repetitive? A team of villains/anti-heroes-who-go-too-far walking around in the colors of the Avengers and claiming to carry on their legacy provides you with the right mix of threat level and immediate antagonism of the audience to get the ground war changed up. USAgent is pretty much guaranteed to be an aggravatingly inadequate-in-character substitute for Cap; apply that idea for multiple Avengers and heroic identities, and exacerbate it, and I think you’ve got fans ticked off the right way, where they have heels they want taken down.
2. You know the X-Men do better when the authority figures are opposing them, but want them to still be able to team up with our known heroes? Just have the Dark Avengers be the officially backed government team, and therefore a display of how dark things have gotten since the Snap, and give the X-Men powerful but flexibly heroic/villainous antagonists to compare against, depending on how you want to play it. The only OG Avengers left all have a past of conflict with the government thanks to Civil War or being interplanetary gods not under SHIELD jurisdiction, so having their government affiliated legacy absorbed by less-altruistic individuals would be a natural consequence of having Iron Man, Cap, and Widow gone. It would also allow both the X-Men and the Brotherhood to be cast as underdogs with a sufficiently powerful Dark Avengers line-up.
3. You want an opportunity to fine tune and exploit great villains in new forms, even to set up arch rivals for the heroes... or even set-up a new Big Bad? You could do the former and conceal the latter with Dark Avengers. Red Hulk, Taskmaster, and an evil Cap/USAgent are all perfectly set up as archenemies for their OG counterparts (Clint especially having a bone to pick with Nat’s enemy masquerading as him could open up a way for him to be succeeded by the new Hawkeye)... and if you want an Evil Iron Man, you could go with Norman Osborne if Sony cooperates... or use another possible counterpart who could turn out to be so much more with a name that sounds like Wictor Bon Boom...
4. You want awesome story ideas that are different from the usual formula? Dark Avengers come with that; you can have them opposed in a movie by the Thunderbolts, for the maximum irony of two teams of villains fighting under heroic identities, but one really wants to be heroic and the other doesn’t, or just have a “New Avengers” VS “Dark Avengers” film.