Bloodborne is being tested on Steam. I doubt there will be a new launcher unless Sony doesn't want their games to sell on PC.It has to release this year anyway. I know they have a console to promote but surely PC and Playstation can coexist just fine especially if Sony are truly willing to extend to PC with a platform of their own.
My personal guess is a new launcher + sub (PS Now with native play on PC, with some 1st party titles hence all the rumors about Bloodborne, God of War, The Last of Us, Days Gone etc..)