Gatx said:
I believe we saw hints at how they would do this with Don Cheadle's replacing of Terrence Howard (small nod to change up but otherwise just keep trucking) and Mark Ruffalo's replacement of Edward Norton and kind of by extension, Norton's replacement of Eric Bana. Norton's movie kind of leaves off where Bana's does and doesn't even bother retelling the origin, and they just pretend like Ruffalo was Hulk the entire time.
I guess what I'm saying is that there is precedent for them just replace actors and reboot characters, and then hoping everything transitions smoothly.
As I understand it, Bana's Hulk wasn't in continuity, since the character wasn't owned by Marvel then. But the rights reverted to Marvel after lying dormant for so long, so Norton's one technically was Marvel, although most people credit Iron Man for kicking off the MCU. That was the time when Disney bought Marvel so everything after the first Iron Man was Disney and in continuity. Ruffalo replacing Norton though is valid and so too is your point about Don Cheadle.
I would say tho in those examples, they're both "secondary" characters in the MCU. They're supporting heroes to the main headliners and so re-casting wasn't so much of an issue, and further, it happened early enough in phase 1 that it's been this way for far longer than it was the other way.
The issue will be with RDJ who kinda headlined and sent the MCU skyrocketing. The option would be to kill Tony Stark in-universe, and explain a replacement in the continuity. To recast without anyone acknowledging it in-universe, it's just Tony Stark with a new face. To retire the character and just leave them off-screen. Or just keep doing reboots. It's not an easy one since continuity is THE reason for the MCU's success; all movies are in continuity with each other, in one shared universe.
You may well be right and just recasting will be enough. It will be jarring but could work. It's gonna happen after this next Avengers, Infinity War P2, the original contracts with the phase 1 lot was 3 standalone and 3 Avengers (IW counts as one film in two parts, sneaky Disney). RDJ would probably be happy to do more but at an exorbitant salary that Kevin Feige isn't willing to pay. Chris Evans wants to move on and has said he wants to be a director. I don't know about Hemsworth's feelings, beyond his quip about "playing Thor after he's let himself go a bit", sitting in Asgard eating and drinking.
