Yeah same, all my favourite MCU films have been the Cap and Thor films, they’re my favourites with a lot of love for Hawkeye Hulk and Black widow.
Dr. Strange is a little too “strange” and obnoxious for me without the charisma of Tony Stark. Black Panther is about as “meh” as they come but I really like Ant-Man and Spidey is cool too, so they could really carry it for me. Captain Marvel also has potential to be super cool.
Recasting is a possibility, pretty much every hero in the Marvel comics has been killed and replaced by someone else. Pretty sure the current Hulk is a Korean dude called Amadeus Cho who took over Banners research after he dies or something.
Thor, Cap, Iron Man, Spider-Man et al. have all had different people take over the powers and roles so it’s a possibility but I think they’ll stick with who I mentioned. Pretty certain the GOTG also has a revolving door with regards to their members.
But yeah Thor and Cap are my faves, with Thor and Hulk being my favourite duo.