Even if it were released with native Japanese support, I doubt that we would see a huge influx of Japanese gamers. W:A is getting really old, guys. I know I don't have to tell anyone this, but as a Japanese person, would you be tempted to play a nearly 20 year old PC game that has little to no following in Japan, the mecca of gaming?
I think that we would have more luck bringing in South Korean and Chinese players, personally. India would also be huge, I think. Even if we did add language support though, how would these people be made aware of it? It's not like updates for old-ass computer games are trending stories on Facebook, lol.