This isn't anything new... Ford is smart to position Mustang as a Global platform. It will save money by offering the car for all markets with left and right hand drive. Additionally Mustang's platform could serve other cars being developed for lesser world markets like Brazil, for example. So this is good news in my opinion.
The bottom line will be.... Can Ford sell their "all new" Mustang to the die hard fans. It's going to be tricky.