I have to admit seeing his new uniform mimick his WWII duds got me a little bit.
If there were to do a solo movie, I myself would like to see something based of Man on the Wall. That comic isn't... awesome, (and some of the artwork is a bit muddled IMO), but the gist of it I think could be really cool. And they could get Mark Hamil to play older, wiser Bucky. I'd die! It wouldn't really be that much of a stretch if after Infinity War (I and II) Bucky decides he needs to get away. Really away. And with Thor, Starlord, and the movies being the second time aliens have come to attack Earth, the idea of SHIELD (or Fury) having a spaceship at their disposal isn't that much of a stretch. Plus, if Agents of SHIELD doesn't get a 6th season, they could include Daisy as the one who goes with him to tie the show more firmly with the movies. And if AoS gets a 6th, maybe Valkyrie would join Bucky. I think they'd get along.
And I can't recall if it was in this thread of the Black Widow thread, but I personally don't think it'd be that much of a retcon to include their connection due to the Red Room. Lack of inclusion in flashbacks that Nat had in Ultron isn't really evidence that they don't' have one. The easiest way to explain why she didn't bring up anything in TWS to Steve is: 1) it wasn't relevant to the situation to mention she trained with the guy she thinks killed Fury. "...the truth is a matter of circumstances. It's not all things to all people all the time." 2) Or at the time she actually didn't remember him from her time in the Red Room because they took those memories of him and she hadn't gotten them back yet. And it wouldn't be that hard for her to mention that when the Scarlet Witch messed with her head in Ultron, it knocked lose those memories. Her very own cognitive recalibration. But maybe not all at once. Her little walk through memory lane right at the moment was just the beginning, and by Civil War she recalled him enough to ask him the question. It's not one I would ask someone who is trying to kill me if I was only referencing other times they tried to kill me. So start her movie with her having more and more flashbacks and goes on her own journey for the full truth, etc. Or whatever.