Rihanna is by FARRRRRR the biggest name he has ever worked for.
I think he's gonna give her his biggest gem(s).
I mean he only started like 3 years ago, if you want to make it big and get your name out you need to deliver A+ productions and the fact Rihanna is the biggest pop star on earth is really helpful as well.
I don't think it will be the same as Unapologetic. Rihanna has always been reinventing and I can't picture her doing something similar to a previous album.