360 did very well overall in Japan, i mean it is an american product directed at a very narrow group of consumers yet it sold more then 1.2 milion in its lifetime, outselling its predecessor considerably. You have to put Xbox 360 into context while discussing Japanese Market.
As for the future? There will surely be another Mistwalker game this generation, that will surely sell well, and who knows maybe they will get some extra JRPG's soon. Japan was never a priority for MS