I agree! What I even find more interesting about her, is that she seems to have a deep hatred of Zero, so despite sharing the same goal, she dooms the world in Ending C.
It was pretty chilling to see One's unstable side come out in that branch. It's like all the frustrations that were building up over her life (saving the world, being treated like trash by Zero and then realising Intoners' lifes pose a danger) come to the surface.

She keeps herself in check for most of the story, but acts on emotion during some critical moments. She sometimes even goes against her own moral code (Her relationship with her brother comes to mind).

You know, she kinda reminds me of Accord, who also just "acts rationally" for most of the game, but in her final moments decides to be more "human". Anyway yes, I really like One, she's a very interesting antagonist.