These changes won’t be added back into the Japanese version of the game, either.
When Dragon Quest 11 launches on the PS4 and PC later this year, it will include many updates over the version of the game that already launched in Japan last year. In fact, there will be so many substantial upgrades, that according to Producer Hokuto Okamoto, the localized version of the game will be closer to a “remaster” than a mere update.
In fact, the western version of the game also uses an upgraded version of the engine (Dragon Quest 11 was built on Unreal Engine 4). These changes will not be reintroduced to the Japanese build of the game, since that will apparently not be financially viable. I guess Square is making an effort here to have Dragon Quest break out in the west, where it has traditionally always been niche.
Dragon Quest 11 is due out on the PS4 and also on PC on September 4. The Nintendo 3DS version of the game will not be localized, while the Switch version will be, but it will be coming later down the road.