If you would have told me at the beginning that we would have two major Captain America films built around him, have him co-star in a TV series, and then be a major lead in another film, I wouldn't have believed it. But putting aside the Falcon and Winter Soldier show, I have enjoyed his arc so far. In fact, I think he's been one of the more interesting aspects of the MCU.
But I also have a hard time seeing him as a serious Captain America replacement. The optics would be really hard for the public to accept. Plus, the overwhelming guilt is relatable and makes him a more interesting character, but would also preclude his ability to be the kind of inspiring symbol that Captain America needs to be. Like Superman, one of Cap's primary personality traits is that of hope and optimism. That's not Bucky.
