Re: MCU: Phase II - Part 1
Keeping Holmes in his original era was more successful, and as pre-modern-tech mysteries, many of the stories could not be directly adapted. Stark is a modern character, so he doesn't have those problems.
He does need to age though, recasts aside, sliding timelines don't do well for movie continuity. Also, unlike Bond, Stark is a character that grows, so recasting, but not continuing his character arc in some way would be off putting, and invite the idea of a reboot, even if the continuity doesn't match making messiness. I really don't like the Bond comparison.
Honestly, without adding any of my faves (BP, Luke Cage, Ms. Marvel) Phase II is pretty much just 'okay I'll see it' for me, like the third Batman. I'm not excited about it. It might be interesting, we'll see. Hopefully they level up Captain America, make his sequel movie really, really impressive, so I don't have to keep seeing Iron Man leading the Avengers in cartoons and stuff. Ugh.