Yeah, I agree that Satori's placement is really odd. I haven't stumbled upon that magnitude of smut of her myself, so I have to wonder if it's a case of "a few quite dedicated artists". I suppose she would have loli stuff though, and I tend to not look for that.
They sorta did that with some characters. Reimu, Marisa, Sanae, and Reisen all had second runs, all at least a little more detailed than the previous, including a costume change. Personally, I'd rather they release new characters. The only three I'd actually buy at this point would be Eirin, Orin, or Junko though.