I see people saying they're hesitant about having Jin "lose her personality". Frankly, I don't think the way she is now is the real Jin to begin with.
I'm not a therapist or a neurologist, but I'm confident I studied enough psychophysiology to learn that our brains don't deal well with stress (especially long term) and, generally, most negative emotions, and it has plenty of fail-safes and defense mechanisms in place (that, sadly, don't always work) to make sure we don't lose our minds and/or break down completely during particularly stressful events/times.
We can all agree that, within the confines of the game world, Jin has been through hell and back for who knows many times (assuming she's been passed around from master to master like a cheap joint as the previous one(s) either got bored and sold her off or died). This "I'm an pro whore and I flaunt it" persona very much feels like a defense mechanism. In that world, she had no say in what happened and no choice in what was done to/on/in her, so in the end, she ended up adopting this persona, either subconsciously or otherwise, to shield herself from further psychological damage.
It has a similar pattern to grief. If you've felt it in your life, you likely know what I'm referring to. We feel sad, we cry, we bargain, and, in the end, we accept. We don't accept it because it gets easier, but because we rationalize that we can't cry forever, otherwise our brain forces us to accept by numbing us down so much until we no longer feel like crying.
Of course, this is all conjecture at best, so take it with a grain of salt. Only Runey really knows what's what.