So, in Stormblood we have both new fox glams from the Foxy Lady Fate, as well as Wolves from the EX trials.
My suggestion is that a fox mount be introduced, whether its a nine-tailed or a just plain giant fox, I for one would do *anything* to obtain it. Cash shop? Check. Ex or Savage? Check. Super Savage? Check-a-rooni!

I think its incredibly important to note as well that the Foxy Lady fate and its corresponding glams are impressively popular and I would be willing to bet that whatever method is chosen to be employed to grant a fox mount it would have a high participation rate.