There's always Bucky/Sarah . The fandom is pretty fond of it. It would be funny if Diamondback appears and Bucky doesn't fall for her.
Family tends to be the more universally accepted subplot. Romance has a higher failure rate in genre shows. Unless it's shonen anime than 90% failure rate.
I'd say the Netflix shows handled romances better than CW.
Bucky/Sarah isn't a comics canon relationship though. That doesn't necessarily mean "never", but Idk if she'll even return.
I agree family works better than romance, simply due to it already being established and not needing considerable runtime to demonstrate the characters realistically developing the relationship
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