It’s arguably the most controversial episode of the show, if not of Trek in general, as Tuvok and Neelix are combined into a single being. The episode raises moral questions and then half-asses the answers, and completely blows dealing with the consequences (as usual). The Star Trek: Voyager Rewatch meets “Tuvix.”
What’s infinitely, horribly worse is that we don’t see how Tuvok and Neelix react to it! Do the two of them feel the same way Tuvix did? Are they upset that he’s dead? Are they grateful? Do they have mixed feelings? This is extremely important information to have. I mean, my guess would be that Tuvok the rationalist is more okay with it than Neelix the emotionalist, but we don’t know.
And it absolutely ruins the episode, because the moral dilemma here is a terrible one, one that results in the captain of a Starfleet vessel—an organization that is supposed to be upholding the Federation’s firm belief in the rights of the individual regardless of what species that individual is from—forcing a sentient being to undergo a medical procedure against his will. On the face of it, it’s a hugely despicable act—it’s so far beyond the pale that the EMH out-and-out refuses to do it. On the other hand, Starfleet is a military organization, and Tuvok, Neelix, and Tuvix are all serving under Janeway’s command, and ordering subordinates to their death is something that every ship captain is likely to have to do at some point.