I have a feeling the lines have been drawn in the sand with the Japanese and MS - it will be awhile before you see another Japanese company work with MS. Level-5, Platinum, etc... these are highly-respected companies in Japan. It's a different culture.
BTW, Nier and Grandblue Fantasy look amazing for the PS4... Like I said before, the lone holdout at this time is Square, and I personally think they've had enough as well (That is completely my opinion). Their games have sold like complete crap on the XB1, and most of them aren't even going to see the platform to tank. PS4 and Switch will get everything Square going forward...
Like I said before, I expect most Japanese companies to take their current XB1 projects (those that actually exist) to Sony or Nintendo.
BTW, Platinum will simply move a lot of their people over to Granblue, which has a following as an established franchise already in Japan.