The initial word on the “Superstar shake-up” was that top names would be moved to opposite brands. The early word, according to the Wrestling Observer newsletter, was that Roman Reigns would move to Smackdown Live and AJ Styles would more to Raw. That was the word a few months ago but, as of a few days ago, Reigns will be staying on Raw and the key moves will be Styles to Raw and New Day to Smackdown Live.
I should add that Styles is advertised for an upcoming Raw live event and they seemed to closed the book on the Styles-Shane McMahon storyline so it does look like his move to Raw is happening. Since John Cena is going to be gone for a while, they need another top star and they solved that problem by bringing Shinsuke Nakamura over from NXT.
The tag team division needs help on Smackdown Live so moving The New Day over to that show is a smart move. For those of you wondering, now that Simon Gotch is no longer with the company, Aiden English will continue on as a singles wrestler.