>>55087743Hokkaido (Sinnoh) was the boonies already. There are still 2 large areas of Japan that haven't been used. Western Honshu + Shikoku and northern Honshu both have potential. Johto only really covers as far West as the Kyoto - Osaka - Kobe metro area with Cianwood being Awaji Island and Ecruteak being Kyoto. That still leaves the major metro areas of Hiroshima, Fukuyama, Kochi, Himeji, and Okayama in the West. Kanto is just the Tokyo Metro Area, so Fukushima, Sendai, Niigata, Aomori, and Hachinohe are all absent.
It's not like they couldn't be made interesting since those areas have unique histories. Northern Honshu, for example, was the last holdout of the Emishi people before the Japanese genocided them. The person who genocided them had the title of Shogun created by the emperor specifically for him, which was later revived centuries later by Minamoto no Yoritomo to use.