A lot of people were sad to hear that Robert Downey Jr. was eventually planning to leave the MCU and his role as Iron Man before it got "embarrassing," but Downey is only leaving the franchise under certain conditions.
Talking to Good Morning America, RDJ says:
"It's like with a team if you're going to hang up your jersey, you want to make sure the team is in good shape and they can still compete at a high level because ultimately that's what made the whole thing worth doing anyways."
That being said, some fans are already wondering who Marvel is gearing up to replace Downey's role as the most recognizable face of the MCU. Tom Holland's Spider-Man could be it, but with the shared license of Sony, Marvel might want to pick someone that was solely theirs.
A lot of fans thought that Benedict Cumberbatch was going to be the next face of Marvel when he was cast as Doctor Strange; but then again, it's possible that Marvel could pick Carol Danvers a.k.a. Captain Marvel to be the new masthead.
Like a lot of fans, I would be sad to see RDJ go, but if Marvel is able to send him off with justice, I would alright seeing him exit the franchise.
Robert Downey Jr. stars in Spider-Man: Homecoming which comes out July 7.