[Allyn Gibson]

I have a mad theory about where the story might be going...

I think that, at the point in time the story takes place, there is no Borg Queen.

I think that something the Doctor does when he "reboots" the Borg to remove whatever the Cybermen did to their systems will unintentionally create a new personality in the Collective -- the Borg Queen.

That's not compatible with Star Trek: First Contact (which indicates in flashback that the Borg Queen was present with Locutus), but in a timey-wimey way it would make sense -- Picard doesn't remember the Borg Queen when he was Locutus because it wasn't there when he was Locutus, but when the Borg Queen tells him she was there she was because she now existed retroactively.

That's my theory.