That said....I'd take FE4's Ayra
You sure you don't want to take that back? Tedius Zanarukando hears all and he will return from the depths of his forum (population: one poster, three trolls) to rant about 'true women'. Yep, now you've doomed us all.
Anyway, does it have to be a girl? Well, uhm... maybe Estelle, the one from Tales of Vesperia? Together we will build the best library ever!
Not much of a choice though. Mostly due to RPG females either being prone to kidnapping (which would get annoying), being prone to triggering some kind of plot based destructive surges of energy (home ownership's a bitch), being prone to dying young (granted this one would too but at least there's a Valkyrie Staff for that (provided anyone could use the damn thing)), being prone to spawning derpy kids (taken care of in this scenario), being prone to be underaged in a rather creepy way (nuff said), being prone to having traumatic pasts (hello massive psychiatric bills), being prone to be useless as hell (especially inside a kitchen, nothing like cooking that's toxic as hell), or some combination of the above.
Granted I might have gone with Samus given that she can kinda take care of herself except for the times when a male with a commanding presence is present wherein she wets her Zero Suit even if said male would shoot her in the back (thanks Other M) but she's not in a RPG yet.
I might go with Princess Peach but she's in a love rectangle between Mario, Bowser, and Donkey Kong and again, kidnapped all the time. Daisy would be worse solely by virtue of the fact that I don't need a significant other who constantly reintroduces her self at the drop of a hat (also not yet in any RPG). Additionally I'd rather not get into politics so pretty much any RPG Princess is out unless they're ones in name only (which means no SD3 Lise either).
Maybe Nina from BoF2 but I bet it'll require soloing Simafort so that's out.
And the list of female characters in RPG LPs I've been following recently goes on and on....
The tl;dr is that most RPG females suck cock already and I just sperg'd the fuck out on a very creepy topic.