So if some of Voyager
's officers are considered "critical", does that mean they wouldn't be allowed to leave the ship if they wished to?
Because if they're allowed to leave the ship voluntarily, then clearly Voyager
-can- function without them, at least in the estimation of whomever is allowing them to leave.
Also, I believe it's explicitly stated in the episode that Tuvix -is- doing both Tuvok's and Nellix's jobs as proficiently as either of them did, and possibly better in some ways. Granted he can't perform both simultaneously, but that seems like a rather unrealistic expectation.
I also wish people arguing that allowing Tuvix to live was condemning Tuvok/Neelix to die would offer an opinion as to at what point Tuvix would earn the right to live. I find it interesting that nobody ever seems willing to address that point.