Honestly, if its just going to be an all female cast I don't care. This isn't a sexist thing, I just don't won't it. The Ghostbusters wasn't about being all dudes, and it shouldn't be about all women either. The comic books have done a good job introducing new female characters, even having 3 women on the team for a short time...but I also don't care much about the new director. I thought Bridesmaids and The Heat were overrated.
There's a flaw in your logic.
The original Ghostbusters were all men, but as you said, wasn't "about being all dudes", but you won't see a Ghostbusters film with all women because it shouldn't be "about being all women". Just because the characters are women doesn't necessarily mean this would be some proto-feminist movie.
Paul Feig, who I believe is running it now, has been making a run of female-lead comedies lately, but for the most part they aren't all "girl power" or anything, they are basically Seth Rogen movies with Kristen Wiig instead. Now, not liking his style or movies is a legit concern, but I don't necessarily think women Ghostbusters is an issue (though an all-woman team does seem an odd fit for this franchise to me).