The original movie Avengers were never written with 'masked superhero' in mind anyway. Stark said "stuff it... I AM Iron Man", so that cat was out of the bag as soon as his first movie finished. Banner doesn't exactly public mingle. He's been running from authorities and hiding most of the time as it is. (Wonder what he was doing between Avenger movies).. Thor is Thor... Captain America you do have to wonder what his civilian life is like buying groceries though. And Widow and Hawkeye are really no different than other 'agent' type characters, be they Melinda May or Sharon Carter. They just happened to become Avengers in the first Avengers movie. They wouldn't have been prancing around in masks and colourful costumes and using superhero names during their past roles, and it's probably too late now.