I don't agree. Bucky will seek redemption for what Hydra did to him, sure. But, I don't see that in the form of Captain America. At this point, Cap cannot die until he puts the uniform back on and gets his shield. Until that happens, Cap cannot die.
Further, yes the comics made other people wear the costume, but this is not comic books. This is a movie series in which the audience only ever knew 1 Captain America. Replacing him with Bucky will more than likely result in either lower BO returns, or Captain America becoming a supporting character, not a lead. The reason to keep Bucky around post-Civil War is easy, he is an interesting character with interesting stories to tell. I think there is plenty of opportunity for a Winter Soldier movie, or use him in future movies as a side character. I just don't see him becoming Captain America. Again, while Bucky has more development than Sam does as Falcon, he has still only ever been a side character. Captain America is a lead: one of Marvel's biggest characters, and the name means something. I don't think Bucky Cap would sell to the masses as well. Cap I think is better served being a mentor in other films, like Stark in Homecoming, and ultimately I firmly believe that is where they're going.