Well, to begin with magical boys couldn't exists because boys barely have the emotional power that adolescent girls do
Taken from the show itself, which I'm watching as I type, Godoka does not prevent despair, she prevents the existance of witches, but the death and disappearance of the puella is inevitable if enough despair is accumulated.

If this goes as I think it does, we are living in an alternative existance in which wraiths are the same as witches for males, not the demons that we see in the remade world in episode 12, and madoka doesn't even exist. However, I bet all our questions are spoilers that the GM is holding to make the story interesting