Why? Because it's the same people whose idea of an engaging all-female party is a clumsy girl in a bikini for no apparent reason, a goth chick they invented out of thin air and who serves no purpose other than being a mopey goth, and a girl in jorts looking for a ghost-zombie (OK, unfair on Yuna, Yuna was alright). They've proven that they can't do all female parties very well because they feel they have to sex them up and give them a hot springs voyeuristic level where you literally sit there on cameras watching them bathe.

Maybe it also means that there won't be a theme (hinted or explicit) of romance in this one. Or that it will be homosexual. That would be a pretty interesting spanner. Or maybe it's some kind of setting where having a female party member does not make sense (like, all of the people in the royal court have to be male for some yet-to-be-explained reason, eliminating the possibility of any females in the battle party). Or maybe they'll pull a Faris and one of them is actually a woman.