And now we've switched from talking about the value of stereotypes in humor to the value of humor more generally. I agree with your statements about the value of humor more generally, and am otherwise tapping out here.
I tend to think of stereotypes as a comedic aid, at least the sort that can easily be discussed here. I think that's why the conversation has shifted. I will admit that I sort of lost the plot, though.
The stereotypes I actually use to guess at people's traits tend to be embedded in details of how people dress, talk, and act - I've successfully pegged people's personalities pretty closely from nothing more than the glasses they wear before - but that's not the sort of thing you can discuss very easily on a text board.
For stereotypes specifically, I think ...
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.