Do you think he's physically capable of doing that?
or would his fans be like "Wait.. who died? Was it implied? Did we miss it?" and keep re-watching it.
As far as happy endings go, I hate them because watching a movie, you can tell from the theme, the style, anything, that it will or will not be happy, generally it will be. So you know the ending. With Joss you keep thinking "Maybe this time it till be happy- look at them eating yogurt together!" He keeps progressively letting you think that it'll be a non-Joss ending, so when when it is, you're surprised. It shows his real skill, in my opinon.