Alex's death makes an interesting change in dynamics on the show. He was an "okay" character with expendable contribution/easily replaceable by a more compelling character, which Bull appears to be so. Even his role in the books can be easily taken over by a new character. The mood in the Roci is getting pretty stagnant with the 4 of them and will only get more stale without mixing things up. There's nothing to be whiny about the loss of a "major" character especially when we get to see more people in the ship next season.