Well, with the way I played Lee, Clem turning out like him would be pretty damn awesome.
She'd still have her own personality, but she'd always try and make the right decisions.
On the other hand, the fact that she's going through this whole zombie crisis in her developing years, and with all the horrible things she's had to witness and take part in, it could have a very negative effect on her too. So that's more where I still see there as being room for player choice and shaping the character.
Not saying this is what I want to happen or anything. I'd be fine with new characters too. But I totally could see this being done well too.