If “Y: The Last Man” were a Word document and you could track its changes, you’d barely be able to see the page for all the edits. The drama’s been in development for long enough to have gone through several showrunners and pilot directors, not to mention a slight network change (from FX to “FX on Hulu”). Now premiering two decades after Brian K. Vaughan and Pia Guerra first published the comic series that inspired it, TV’s “Y: The Last Man” takes obvious pains to imbue the story — about the aftermath of everyone on Earth with a Y chromosome suddenly dropping dead — with more nuance on sex and gender than its 2002 iteration. With so many transitions and considerations at play, it’s a wonder there’s anything to show for it at all, let alone anything as generally solid as what this version of “Y: The Last Man” offers up. For all its canny calculations, though, it also feels stuck in a single, grim gear that threatens to flatten its greater potential.

“Y: The Last Man,” now showrun by Eliza Clark, spends minimal time in the before of the so-called “Event” before plunging straight into the hellish after. (It’d be shocking if the logline for this series doesn’t include some iteration of, “think ‘Battlestar Galactica’ meets ‘The Walking Dead’ divided by ‘The Handmaid’s Tale.’”) In the brief time the series spends in a world resembling our own, we learn enough about each main character to inform their evolution through the horror to come and beyond to the intimidating unknown. Jennifer Brown (Diane Lane) is a liberal-ish congresswoman who has no problem telling the conservative president exactly what she thinks of him. Lane, one of the only actors attached to the series throughout its many iterations, is excellent in the part, which challenges her to be steely and vulnerable all at once. Meanwhile, Jennifer’s kids are decidedly less ambitious than she; her daughter Hero (Olivia Thirlby) is a self-destructive EMT while her son Yorick (Ben Schnetzer) is an aspiring escape artist living on Jennifer’s dime. (Before you ask: yes, their father was a Shakespeare professor.) No one, least of all Yorick, expects that he’d seemingly be the only man with a Y chromosome to survive the Event. As he himself says in gob-smacked awe, he’s “just a guy” — albeit a guy with a male monkey who also, for some reason, is still alive.

This trio, forcibly separated after the Event, forms the core of the series as their storylines intersect and diverge. After a decimated line of succession makes Jennifer the President, she reluctantly tasks Agent 355 (Ashley Romans) with bringing Yorick to a geneticist for answers. Hero, meanwhile, resists returning to her judgmental mother, even though her resources could ensure her safety and that of her best friend Sam (Elliot Fletcher), a trans man who’s now running low on testosterone and under a microscope like he hasn’t been in years. Why “Y: The Last Man” is still the title of a show that acknowledges Yorrick is not, in fact, “the last man” is probably down to franchise recognition, but is strange nonetheless. Trans women, meanwhile, are notably absent altogether.

Though Yorick and Hero are ostensibly the stars of their stories, it’s 355 and Sam who end up anchoring the far more compelling arcs. Acknowledging that trans men would be under a completely different kind of pressure than ever before is an important adjustment for the show to make, and Fletcher ably handles it. And as 355, a character that would inevitably be an inscrutable older man in many other narratives, Romans gives the show’s bar none best performance. Her character might not have a name, but she does have a distinct energy, pathos and determination that handily carries her scenes through to the next.

Balancing the show’s many different plots, not to mention the myriad avenues its premise could yield, is a challenge “Y: The Last Man” embraces, but doesn’t always conquer. As a government employee who finds herself fending for her life without much practical survival knowledge, Marin Ireland quickly gets lost in other characters’ journeys. Amber Tamblyn does an admirable job in the role of the former president’s equally conservative and ambitious daughter, but rarely gets the room to embody many characteristics beyond “conservative and sad.” Politics outside the president’s war room are generally relegated to whispers and strangely verbose rebel graffiti (“SEXISM DIDN’T DIE WITH MEN”; “RACISM: AS AMERICAN AS BASEBALL”). Bucking the trend is Missi Pyle, a perpetually compelling character actor who turns in an atypical but very sharp performance here as a detective turned survivalist cult leader.

As with every apocalyptic drama, the premise of “Y: The Last Man” gives the show almost too much material to mine. There are countless ways a mass Y chromosome casualty event could manifest and affect the world thereafter, but only so many minutes with which the show can demonstrate them. Throw in the show’s uniquely hard road to the screen and it’s no wonder that it can’t quite handle all its ambitions. But the real undoing of “Y: The Last Man,” at least in the first six episodes provided to press ahead of the show’s premiere, is that it takes itself too seriously to allow for many other emotions beyond “desperate” and “grieving.” Even the style of directing, while ably established in the first two episodes by Louise Friedberg, tends towards the dour, with the occasional exception of more energetically tense scenes when Roman’s 355 is concerned.

On the one hand, “Y: The Last Man” is a dystopia drama, so of course desperation and grief would reign supreme. On the other, it’s a human drama, and as such, could use more shades of the human experience to make it resonate even more strongly. It’s strange, for instance, that lesbians and queer women barely exist throughout the majority of this first season. It’s frustrating, too, that the only character seemingly capable of cracking a joke is Yorick. Even aside from the obvious Representation Matters of it all, the lack of humor and romance in the series represent sorely missed opportunities to create a more complete, believable world. Even while furiously grieving, human beings are able to laugh, flirt, and dream bigger than our circumstances might allow. “Y: The Last Man” acknowledging as much wouldn’t betray the genre, but enrich its own reality to become more recognizably poignant — and, yes, harrowing — than the monochromatic pain to which it otherwise defaults.

“Y: The Last Man” premieres September 13 on FX on Hulu.