I kinda doubt that Feige will try to do Dark Phoenix after the last attempt, at least not for awhile.
Secret Wars, if done properly, in my opinion should lead into Battleworld. But I rather them do the Dr Doom storyline rather than Beyonder personally. And I sort of suspect they are heading in that direction, especially if rumors of them considering dropping Kang is true.
I don’t doubt that is the case, I’m offering up where they could go not where they will.
Some of the decisions they have made on what movies they have put forth are baffling when Dark Phoenix has been done so badly. It’s always in the top echelon of greatest Marvel comics storylines of all time. I get that it’s not in the current MCU, prior property of Sony film wise and all that.
All that said? “Hey I know let’s release Eternals as a movie!” When I heard they were moving forward with it as a movie a few years back, my reaction was one of bewilderment as nearly all of the movie going audience would no idea or care who they are and it showed in the results. Eternals? Really?
If Marvel is looking at teams of super heroes? There are a few they could go with, but likely won’t:
Defenders- they’ve always been seen as a sort of B list Avengers, I only offer them up; personally I’m not sure where they go with them if at all.
Invaders- this could work if done right but would required Chris’s Evans, I’m not sure he’d want to do it; as in not likely. But a movie or triology in the vein of Captain America, First Avenger consisting of:
Captain America
Union Jack
Spitfire
Toro/Human Torch
Sub Mariner
That’s the core, fighting a nazi bad guy like Master Man or Baron Blood.
As to the likes of Whizzer or Miss America maybe but those two would likely need to be changed of included for the big screen. Whizzer because of Quicksilver already on screen and Miss America being somewhat underpowered in the comics. That’s an easy enough fix in the MCU.
First Avenger had a warmth to it that especially with the MCU movies now is lacking.
Consider the Howling Commandos in the movie and Bucky and then contrast with Eternals. One the audience cares about if only because Cap does. The second? Most are left scratching their heads.
Throw in some cameos of Agent Carter and Bucky, Howard Stark and there will be some natural tie ins.
A lot of this is just throwing stuff at the wall and unlikely to ever happen. WW2 era super hero stuff should be unifying for a movie going audience, but I could easily see issues which I’ll leave out as it’s likely to be a divisive topic or topics for the site.