I've been thinking about this post since I first saw it, actually, and am trying to sort through all my thoughts about what does and doesn't work for me. If it's fic recs you want, though, you can't do better than Some of the Colors Have to Fade, which is Bucky/Nat and which is all about confronting and throwing themselves into the utter wrongness of "murder buddies who sleep together," why that's necessary for both of them and figuring out what to do next. (I'm not doing it justice here, but it's really, really good: Nat is decidedly the thoughtful, ambiguous troll from the scene in the truck, and Bucky comes back into himself in a way that makes sense to me.) It also takes place a little bit after Bucky comes in; there's a companion story before it, but you don't need to read it to get this one.