Given the rather bored (I wouldn't quite say "negative," but certainly "unimpressed") reaction even Japan had to loli Rorona from Meruru in general, I don't think they would be too averse to an older character. Totori definitely got Rorona's maturity right in that regard.
I think there's a lot they can do with the female characters, but they're afraid to venture out too far- and quite honestly, given the state of Japan's market, I don't entirely blame them. Whether or not you realize it, there was a huge shitstorm when the Iris games were released. At least they seemed to have learned their lesson from AT3 in that overt sexuality doesn't necessarily make a better game. Having a character who needs to be protected isn't necessarily a bad thing, given Alchemists for the most part aren't fighters, they're crafters. For me, the issue is that, for the most part, they all have relatively similar personalities despite their quirks.
But Iris from Iris 3 is a lot like what you seem to be looking for, yes?