The keyword is "program". I think that we can also say "wish" instead of "program". The main problem is that Japan doesnt export its weapons. It means, that they will never develop totaly new fighter because of the costs reasons. If the ATD-X be build, also its name suggests that it will be only flying testbed for a new technologies. Technologies that will be implemented in some modified foreign plane like in F-2. And the quantity and quality of modifications once again depends on available funds.