As a feminist, I really don't see this as an issue. If it fits in the story, it fits. We have this wolf pack dynamic between the characters, going on a road trip - it is something new that seems fresh and if throwing in female characters just to please fans would compromise that, then I don't think they should. Let's just watch and see how this plays out. I'm pretty confident that the dynamics between the characters will be awesome.

Also, X-2 had an all-female party. I liked that game despite it's terrible story and thought it was really fun, and I don't really remember anyone complaining about the lack of male party members.

So let's just see what the creators have in mind for them I'm sure it'll be different, and different can go both ways. I'm pretty confident it'll at least be fun.