Yeah; I don't have a specific narrative kink for it (beyond just being a sucker for family/found-family in all its permutations) but it's really fundamental to my love for these particular characters' relationship and this incarnation of it. I do like their comicsverse versions as well, but they are very different and the movieverse versions are, for me, largely defined by having been so much a part of each others' lives for so long. And it's really kind of confusing that most people writing AUs don't seem to see that as a fundamental part of their relationship! But I think a lot of it is just to do with shoehorning Steve/Bucky into standard-type AU slash scenarios without really thinking about how it goes together with their canon relationship -- probably because you can do that with most major sci-fi fandom pairings (including, say, Steve/Tony) but not with those two.