It is illogical to kill Spock. That is what fans were trying to tell Paramount back in the early 1980s when it was discovered that Spock would be killed at the end of Wrath of Khan. I love that instead of a letter writing campaign or some silly stunt, they prepared a logical analysis of projected profit loss to try and convince the studios to change the plot. I think a Vulcan would be proud (if they acknowledged pride).
Luckily for all of people who grock Spock, his death was a short one and all this hullabaloo was for nothing. Plus we got one of the most touching death scenes ever put on film with none of the loss of perma-death.