I think after Infinity War, if you're smart you let those characters retire and bring in a new crop of heroes, with (gasp!) new plots, perhaps even ones that haven't already been in the comics.
I guess they are going to introduce a lot more character fast or else Civil War is not going to be that exciting with the relatively few super power persons we have seen.
Actually, they'll probably just soft reboot the universe with Infinity Gauntlet magic or something.
I imagine Tony Stark putting on the gauntlet and sacrificing himself to get the universe back to a pristine state.
If you're going to do that, just go for broke and have the entire Marvel Cinematic Universe be a dream sequence of a young boy who fell off a ladder and hit his head. Audiences *hate* the, "erase the established history" resolutions.
My hope is that Marvel alters it's formula now; the movies are starting to feel very formulaic to me. I started noticing it during that final battle in IM3, and by GotG I was really noticing it.
For me, Marvel's had about a 50% hit rate with the combined universe slate - Cap1, Thor1, IM 2 & 3, the first Hulk were all misses for me. IM1, Cap2, Thor2, Avengers, were all hits. GotG would have been a hit in isolation, but I'd reached peak formula by that point.
The two latest Spidey flicks were both misses, as were the two F4 flicks. Wolverine bores me senseless now, but there's most recent X Men movies were excellent.
So 50/50ish in all. I can live with that, but they do see to change things up a bit to retain my enthusiasm.
I kinda liked the mystery of what they would do next, the after credits hints, the speculation, the slow reveals, etc. I'm
Not sure I like this big public fanfare announcement event approach. Takes some of the fun out of it. Plus we know exactly who's going to be sticking around for the next 10 years or so.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.