I would absolutely be fine with Dex 10, Cha 12 if the Charisma is part of their vision for the character. It's really just the negative Dex modifier that makes me not care to bring her along anywhere. They could also bring her INT down to 8 to take CHA back up to 12, or put DEX at 10 and INT at 8 if they really, really badly want her CHA to be 14 for whatever reason.
