Joe's death felt to me a bit Whedon-esque. The randomness and sometimes senselessness of it, also the idea that no one has really any control when it happens, it happens.
Needless spoiler here: When Shepherd Book denied in Serenity we kind of saw that coming but the additional death of Wash was the kick in the nuts as "we" mostly did not see that coming.
Sure it's great to have a great storytelling moment or a climactic plot moment where Our Hero goes out in a Blaze of Glory.
In reality this rarely happens and I would call SoG a bit of SF with some hard science to it so some verisimilitude works with this.