I imagine that at some point in Season 2, it will become a thing again.What was incoherent or irrelevant? It all informs us of where Cassian came from and what he's about. He doesn't need these things to feel bad about leaving Maarva or caring deeply about Maarva, but they do give us an expanded context about their relationship, who they were, and why they feel the way they feel. They are hardly irrelevant.
And it's okay for some things to not be resolved. If anything, it adds to the realism of the entire situation: sometimes life interrupts what you want to do and changes everything. Cass killed a person, and that changed everything about where he was and where he was going; that doesn't mean it wasn't meaningful, it just means that he hasn't been able to get back to it. Perhaps he never gets back to it, but that doesn't make it irrelevant, it just means his life has changed in such a way that he can't or he doesn't desire to.
If the arcs that are mentioned above are correct - with the 4 years being covered by 3 ep stories each, then I imagine that one of those four years will resolve this.
I do kinda like this plan though. Each year is sort of a mini-movie - more or less a 90 minute movie leading up to the movie. Very cool idea.