Originally Posted by McSir
Wouldn't have worked. Bucky was such a non-character in the first movie that if they waited until the third movie to bring up the Winter Solider for the third movie almost everybody in the general audience would've all but forgotten about him.
Plus, if you save all the cool stuff for some point in the future you have nothing to fill the present.
Winter Soldier isn't the only worthwhile Captain America storyline, you know. There was a period of about forty years between Cap getting thawed and the Winter Soldier storyline, pretty sure there was one or two characters or storylines you could make a non-Winter Soldier movie with.