The story itself is all up in the air right now, still plotting a course. But I'm never opposed to more bimbos, I just don't want to get greedy, or have an abundance of unused assets at the end of the demo.
As for the S-Link itself, I believe, and Dev can correct me if I'm wrong, it relates directly to the advancement of the story. Whereas with BrainLight Dorkle it was helping her get her stuff in order to get into the McGuffin Program, with HeadLight Twaddle it will be getting her comfortable with her oversexualized body, and the needs it has therein. And the success or failure depends on her own stats; I'm thinking Charisma is the primary in this case, with INT taking a second - the higher both of them are, the more likely she's going to stay, uh, reasonable. As in she's able to stay in control. Not sleeping with everyone with a pulse. Or, if you like that kind of thing, ending up as a school bicycle. Point being, once you get to this storyline, Twilight is going to be a bimbo. How she gets to where she ends up, that's for the S-Links to tell.
That is an interesting idea about the S-Link being tied to Twilight's slide down the storyline. We might be able to associate additional transformations with S-Links (maybe not 1-to-1, but by S-Link 7/8, if she could finally reach her Bimbo 10, that would be something like what I'm thinking), but that's a coding thing, so I don't want to stray too far into that.