My use of "all-female stunt casting" is just meant to conveniently mush together a couple of concepts that are going on simultaneously. To me, "stunt casting" is whenever you specifically cast somebody for a part because it's not what people will expect, and thus will get people talking. There are casting choices that are unexpected, and then there are casting choices that everybody involved has to know will generate a shitload of media buzz. So you're gonna remake Ghostbusters. Okay, then you better have a pretty fucking good idea what you're doing because you're talking about remaking Bill Murray, Dan Aykroyd, Harold Ramis, and Rick Moranis in their prime. (Yes, I know Ernie Hudson was the fourth Ghostbuster, I'm not an idiot, but he was an unknown at the time and Rick Moranis was not.)
So someone says "Okay then, who are some of the hottest female comedians right now? What if?" And the room is silent for a few, then people start throwing out names. "Kristen Wiig!" "Um, that one black chick!" And so on. So, a specific casting move which they absolutely had to know would generate buzz. I'm not saying it's good or bad. It can be both, or neither. Not a problem as long as the movie is good. But they had to know it would build hype, so they had to know that this can help sales, but also raise expectations unrealistically high.
Hypothesis: Those earlier trailers made the movie look awful on purpose in order to lower expectations, or at least put a check on them. They didn't want people to go in with insanely high expectations becuase that would be impossible to meet, so they let the media buzz go on for a bit, they release a trailer that actually makes the movie look kinda shitty, they wait a little longer, they put out the infamous review ban (which builds more hype but being a move usually linked to movies which suck and everybody knows it, the hype is again intentional and again meant to lower expectations).
Then the movie comes out and it's fine. A lot of people are saying it's fine, it's funny, it's not a waste of time, whatever. I never said "all-female stunt casting" was bad; it just is. I'll watch the movie; I'll just wait for cable or DVD to catch it.