Jag, "so that AMGN becomes the owner of AFFY so that both Takeda and AMGN benefit immensely." Interesting theory and for this to playout there must be a lot of other business between Takeda and Amgn for Takeda to let go of control of affy since they financed the Hema development to date.
My guess is that Takeda takes affy home but there is still room for a friendly relationship with Takeda & Amgen providing it is not anticompetitive. Certainly, if Takeda takes affy that may test the partnerships between Takeda and Amgen on other drugs.
Also, believe Arlene (world's best stock trader) serves as the affy ceo at the pleasure of Takeda and stays as long Takeda decides. At this point, it is just a babysitting job; key decisions are made by Takeda most likely. Would suppose her large stock sales were negotiated for Takeda to purchase and indicate her short time status.