Trek to me has always been about characters first and spaceships second, and the characters that have always been most engaging to me are those who are struggling to understand some element of their "humanity"--Spock, Data, Odo, Voyager's Doctor, 7 of 9--since those are stories with a universal perspective and commonality. (And it's one of the things that Enterprise was so desperately lacking.) Ironically, it's also the kind of story that can really only be told in a sci-fi context, unless you have an ordinary drama with a character who somehow doesn't understand what it means to be human.
From a writer & editor's standpoint, too, it's where you can have the most creative freedom, since it explores a character's inner life without having to worry too much about the big sweep of continuity. If in your story you want 7 of 9 to develop a deeper understanding of one aspect of human relationships, it's probably not going to be derailed by fidelity to canon.