If I do, it won't be using this current 'stat placeholder'. Ultimately everything is going to come down to how it interacts with the booths, either directly (you get more resources) or indirectly (her skills increase a bit faster) and I'm not sure a disadvantage plays too well into that loop.
I'm all for things the player has to play around, but I think it's better if a player's challenges come from the environment (the clients) rather than the roster. Openness, for example, and ability to do a job, is a pressure from the client so it doesn't 'feelsbad' if a girl isn't levelled to do a certain act. You have a problem, but you have a solution--either level her more or toss the negotiator at her.
But if a girl had the trait 'Will never Oral' just randomly, well, that's just not something you can easily just 'fix' in the same way. About the worst I think I'd be willing to let that go is already with the current 'Won't Do' system, which with key 'won't do's is already enough to make a girl difficult to use or underpowered.