The Tuvix debate is stupid. It's the most asinine debate point we have in this entire fandom. For those unfamiliar, the Tuvix debate revolves around an incident in Star Trek: Voyager, where the characters Tuvok and Neelix suffer a transporter accident, where they are combined into one, singular entity; named Tuvix. He has all of their memories, but his own unique personality.
Captain Kathryn Janeway eventually resolves to put the new person through a process that'll separate him back into his two prior forms. Not everyone was on board, simply because it wasn't an easy decision to make. Tuvix didn't help the matters, but in the end, it was the right decision; as the needs of the many outweighed the needs of the few or the one.
It's something so many fans, who just seem to want to be contrarian forget. Not Tim Russ, however. Russ played Tuvok on the show and when the topic was brought up during the third annual Trek Talks (via TrekMovie.com), the conversation was brought up to the digital panel and Russ nailed why Tuvix had to be split back to his former forms;
"The captain’s responsibility is to her crew. That’s what the captain’s responsibility is. And she’s the only one on the ship that can make the decision. And he [Tuvix] cannot reproduce as a species… I believe that point is made [in the episode], there is no other of his kind… He’s an anomaly, whereas the crewpeople that he has replaced already have a family, we have lives."
And he's right. If Tuvix wasn't so sentimental, people would see that. Tuvix didn't have any connections and he didn't have any family. His sheer existence caused two people to stop living. He killed them by existing. He didn't ask for this, and he wants to live, but his sheer life means that two others are gone, forever. Men who have families, vital roles on the ship, and lives that were shunted for no reason.
They deserved to live, just as much as Tuvix, and if Tuvix has to die so that Neelix and Tuvok can live, then so be it. It's the right call. And let's be real, the only reason anyone actually liked Tuvix is that it got Neelix off the show for a bit of time, and fans, for whatever reason, really don't like Neelix.