Instead of trying to validate her sales drop as something normal, I think she should indeed take a few steps.
Crazy bonus goodies like Koda Kumi. Koda's marketing tactis holds me in awe.
Now with the slot machine scheme, I can bet Black Cherry will sell a lot. And the single + photobook thingy too must be done, like with Maroc. More unique photoshoots. And dramas, instead of just making a tie-in, STAR IN ONE, DAMNIT. Main movie songs, like HEAVEN is vital. She hasn't done a proper big name tie-in since HEAVEN.
No stripping or boob-baring, that'll just lower sales. Janet and Courtney Love = Living Proof.