Personally, I really like physical transformations and bimbofication. The reason I liked the "Gyaru frenzy" extra so much was because of how extreme Emily and Abby's transformations were, both physically and mentally. Seeing them transform from their original selves into barely recognizable sluts with huge tits was incredibly hot to me.
I completely understand if most players aren't into that kind of thing though. That's kind of the difficulty of making a porn game with broad appeal. Everyone has different tastes and one person's turn-on is another's turn-off. I guess that's part of the reason the "extra" scenes exist, so that the more niche fetishes are available, but avoidable.
You mentioned once that Gyaru Frenzy would be getting a sequel eventually. Do you think that will be happening relatively soon or is that much farther down the line?