There's absolutely something there imo. Just the fact that there are normally no female-looking pure titans is really interesting in the context of everything we've learned. The Female shift form itself is most likely something unique to this whole mess.If the Attack Titan is her impulse to fight against something, maybe the Female Titan is her feminine... something. Compassion? Nurture?
It's the only way I can see Annie making a difference.
Maybe her scream in the woods during the Female Titan arc was somewhat of a motherly, "CHILDREN, COME RESCUE MAMA" since all titans ended up descending from a female titan at the start of things.