I've come to feel that "The Slaver Weapon" is overrated, frankly. It's not really a
Star Trek kind of story. It doesn’t have anything to say — no thematic or philosophical subtext, no message or commentary. It’s just a problem-solving exercise and a battle of wits against an enemy. It’s unique in TAS and rare in Filmation’s ouevre in that it ends with the villains being killed outright rather than reasoned with or outwitted. Despite being fairly action-heavy, it’s incredibly talky; the first act is largely one long monologue by Spock to fill in the backstory, which is a clumsy way to write a TV script. It also has a really weak and awkward ending. Even aside from the questionable taste of laughing about the deaths of one’s enemies, that last exchange about Kzinti superstitions isn’t even funny.
The attempt to adapt "The Soft Weapon" to TAS with minimal plot alterations introduces some logic holes, too. For one thing, why doesn't the weapon's power dampener setting shut down the force field belts? That wasn't an issue in "Soft" because the characters were in spacesuits. Also, the episode changes the box's origin by saying it was found on Kzin rather than purchased from Niven's Outsiders -- which creates a huge ethical problem, because it means the Kzinti have a legal right to it and Starfleet stole it! (Granted, there are references to a treaty, but it still feels like imperialism, a conquering power plundering the loser's cultural heritage.) Additionally, referring to Spock as an herbivore is incorrect; he's an omnivore who chooses to be a vegetarian. Nor is he a pacifist. So he doesn't fit into Nessus the Puppeteer's hooves as well as the episode pretends.
I can imagine a more Trek/Filmation-style ending to this episode: The Kzinti bring the captives out with them to test the weapon, so they’re all imperiled by the self-destruct, and Sulu and Spock urgently reason with Chuft-Captain and tell
him, rather than each other, why they’re convinced the weapon is going to blow up. The Telepath chimes in that they’re telling the truth. Chuft-Captain hurls the weapon away at the last moment, they’re all saved, and C-C’s honor debt compels him to let them go. The closing dialogue is about the hope that this act of mercy and understanding may have opened the door to peace negotiations with the Kzinti.
The real question is why aren't we getting some big screen version of Niven's work?
Good question. I think Syfy's been working on a
Ringworld TV miniseries, but given their track record with miniseries adapting classic SF novels, I don't have high hopes for its quality if it does get made.