The Thunderbolts could have a *lot* more flexibility in terms of their roster, though I don’t think an MCU Dark Avengers would necessarily need as much of a 1-to-1 ration of Avengers counterparts, but would need equivalent powerhouses and sufficient heroic identities to believably frame themselves as successors to the Snap-ending Avengers, rather than impersonating the original members. That way, you can build into an in-universe narrative of them trying to run a long con with fewer outright deceptions.
Red Hulk feels like a gimme to me, just because he’s a decent evil counterpart who could still masquerade as a hero “honoring” Banner’s legacy. I don’t know if I’d have Ross turn into him, though, but if he did, I’d be up for a dramatically different physique for Red Hulk along with his heat-based power-set: maybe he’s got a more lean and veiny build, and he’s bald.
Black Widow II also feels like a gimme, since you could again just have her deliberately play herself up as Nat’s successor.
I really like the idea of Taskmaster instead of Bullseye for the badass normal character, at least in part because a strictly professional mercenary seems like a better fit than a psychopath who kills people for fun, and I’d enjoy having someone as uncomplicated as Tasky to contrast with everyone else on the team. Plus, they could believably make “Taskmaster” his public “heroic” identity; it might even be funny if he despises all the pageantry or super-villainy and super-heroics and has to put up with it.
I feel like Moonstone should be introduced and made into a Captain Marvel counterpart right now, just to bolster the team’s power and bring up their gender imbalance by taking Thor’s spot on the roster. However, since I think “successors” should be the pitch their giving the public, maybe she goes with just Moonstone or Photon or something?
It’s Cap and Tony whose counterparts feel a bit more difficult to me; I actually don’t want Iron Patriot, partially because Iron Man 3 already used the suit, but partially because I’d rather have Osborne try and become the Nick Fury counterpart and just have Green Goblin be his powerful alter-ego.
So how’s about this for the counterparts for Cap and Iron Man?
For Cap: of course, USAgent provides the framework for how to replace him, but I’d actually like it if they went with the more obnoxious “Super-Patriot” identity, and maybe kept the USAgent identity for a more self-aware and inherently more cynical would-be-Cap character for Falcon and Bucky’s TV show. So... I’d say John Walker as USAgent for a more morally ambiguous character (who could maybe join the Thunderbolts after being set right by Sam and Bucky), and then William Burnside as Super Patriot... or even just have him have the balls to insist he’s the new Captain America.
Okay, here’s the crazy one: to replace Tony Stark?
Doctor Doom.
Now, no duh, he wouldn’t call himself that, but consider how good of a twist that would be: the replacement for Stark is also a counterpart for Doctor Strange and for Black Panther. And that could be how you’d introduce the Fantastic Four elements.
