I believe that the "kink" system should tie into the whole "self-esteem" or "satisfaction" system, or whatever it is going to be called. My idea is this: while in college, the MC can gain kinks at the player's discretion, but they lower her total possible amount of self-esteem (let's say it starts at 100, and goes down by 10 for every kink she accepts). However, when faced with a task that would normally be repugnant, like stripping onstage to win a contest, she can do so without the kink but at a loss of self-esteem. If she has the exhibitionist kink, she can do it with no loss of self-esteem. Losses of self-esteem would be recovered by being successful in some portion of her mission, or by side quests like bugging the phone.
Maybe having sex with men she finds handsome would raise self-esteem, while having sex with men she finds hideous would lower it. Similarly, having sex with malicious men might lower self-esteem while sex with solicitous men might raise it. There are all sorts of possibilities, most of which Crush has probably already worked out.
In essence, then, the character you "build" through choices in her life story would be more easily able to do some kinky things than others, and the player would want the MC to make choices that allow her to exploit kinks, where possible, but can tactically choose to lose self-esteem where that would seem to have a higher likelihood of mission success (thus counteracting the loss of self-esteem caused by the MC doing something kinky that she isn't into). Some randomness to the process would keep it from being too predictable.
The key to interesting player choices is making the costs and benefits of certain choices somewhat under player control but a tiny amount not under player control (no certainties). This, you could choose to make your agent have lots of kinks, but that would also make her lower in maximum self-esteem and more vulnerable to strings of bad luck. Complete loss of self-esteem might lead to a "pull me out" game over, or even a game over where she decides she's nothing but a whore in truth, and she abandons the mission and stays in Bangkok and works as a stripper and whore for real.
She could even end up in situations where she has no choice but to engage in kinks (she'd pretty much have to be an exhibitionist after stripping long enough in Bangkok) and involuntarily acquire the kink and lose the self-esteem when she realizes she likes that sort of thing. If self-esteem were low enough through previous choices, this might cause a game-over the player didn't intend.
Some kinks would be more useful than others. If it seems necessary to balance that out, the permanent cost to self-esteem could vary by kink acquired. "Likes older men" could prove to be less useful than "likes rough sex," so maybe the permanent loss of self-esteem is 5 for the former and 15 for the latter.
If this suggestion is adopted, a useful kink to add could be "has low standards," which would limit the loss of self esteem for having sex with men she doesn't care for.
Anyway, once again, just some unsolicited suggestions to be taken or left as desired.