FWIW, I totally agree with Sci's post.
But as I said, the issue with Tuvix is that he acted selfishly. He placed his own survival above that of others, and even took aggressive action to try to preserve his life. Now, from his perspective, that was understandable, but what about the rest of the crew's perspective?
How can it be selfish if a person wants to survive? It would have been different if Tuvix's death actually served some other purpose than to make the crew feel better - so, who's selfish there? IMO a crew who can't cope with two of its members gone isn't the most stable crew anyway.
After what Tuvix did, they wouldn't have accepted him anymore, and that would've damaged crew cohesion and possibly had dangerous consequences in crisis situations. But the rest of the crew would still trust and accept the restored Tuvok and Neelix.
I definitely don't agree there. There was no crisis situation when Janeway ordered Tuvix to die. The crew's livelihood wasn't threatened in any way. They would have needed time to come to terms with reality but in the end they would have come to terms with it and let go.
Tuvix never would have hesitated to lay down his life if there had been a real threat to the crew. I don't think that the crew doubted that if they had taken a step back and actually thought about the situation.
Honestly, I rather think that not so important crewmembers should consider the fact that they could be sacrificed needlessly, just to make the higher-ups happy. Talk about a boost of morale.