Generally it feels like most similar games like to make the stats feel more 'realistic', but I agree that realistic and completely sub-optimal aren't the same thing. At the same time, I think that most designers don't want to use extreme or perfect stats without a good reason. My guess is that choosing a physical or mental stat under 10 would need to have a good reason, especially an INT below 10. Those are the places you get to play with things like stupidity, clumsiness, and frailty.
Personally, I would suggest something that would leave more options open to the player if they want to multi-class her. Something like 13 11 14 16 10 13. This leaves most of the sensical dual classing options open and the opportunity for her to grow into whatever stat focus you want. Yeah it makes the first few levels less than optimal, but it leaves her with the most room to grow into what you would like, while keeping the flavor that I think they were going for. At a minimum, just pulling the CON down a point to push up the DEX would be a solid improvement.
