Why, anon? I'm loving the slowness of it all. The update speed could be faster, but I'm not going to complain if it arrives on a regular basis. It maybe even helps in a way, drawing it out. :D
For what it's worth, I'm enjoying this a hell of a lot more than the typical "turned into a girl, suddenly too horny for self-control, oh I need a man, God I love being a slut" progression that has been so common in the genre. The fantastic quality of the artwork aside, I'm thrilled to see a much more tasteful approach being taken. And seduction does tend to work much better than brute force.
I don't always have something specific in mind when I change the color palette, but I like the varied interpretations. As far as magical manipulation, conventional manipulation, or the transformation being more than skin deep - slave girl doesn't know so we don't either.
Keep in mind that since she's the one 'telling' the story, we might not be getting a completely honest assessment of her motivation.