I don't have any expectations either way. However, I do think there is a problem with 'girl bands'.
It's not the fact that they're all female - more that they use it as their sole advertising schtick. A couple of groups seem to rely mainly on the absence of phalli in their membership to sell their music, rather than their actual talent. This can happen in mixed-sex groups as well; everyone raves about Angela Gossow of Arch Enemy and Simone Pluijmers of Cerebral Bore because they're women, not because they're good.
By contrast, Runhild Gammelsaeter of Thorr's Hammer actually is a good vocalist (or so I hear), but that's not the sole or even primary selling point of the band. Simone Dow of Voyager is a pretty good guitarist but the band never makes a big deal out of her sex. The same goes for bassist Roxanne Constantin of Quo Vadis and keyboardist April Sese from Suspyre. It's not impossible for women to be good metal players, but typically when they emphasize their sex as their defining characteristic in plugging their band's material, it suggests that they are compensating for something.