For those wondering about localization, it seems to be a trend for SE to localize a DQ game if it sells over 1 million in Japan. There are a handful of exceptions to this rule, but they're all explained easily enough by the circumstances of a given generation. I don't think it's so much that the last two Monsters games wouldn't have sold in the US, but the fact that they failed to break a certain number of Japanese sales within a specific amount of time, so SE was lacking confidence that sales would work out in the rest of the world. I mean, imagine that, on a popular release they can only expect around 10% to 20% of Japanese sales on a DQ game throughout the rest of the world. If the game sells 1 million, that indicates that they can expect upwards of 200k more sales throughout the rest of the world, which can be considered good enough, whereas if the game has only sold around 790k like the most recent Monsters remake, that's at absolute best a projected 158k with it likely only hovering around 100k sales in the rest of the world.
SE does seem to have some kind of defined expectations for the sales of DQ games in Japan before they'll consider localizing them for the rest of the world, regardless of spinoff, remake, or spinoff remake. It probably has something to do with the fact that DQ is their prize jewel right now that they haven't sullied yet like Final Fantasy.
Honestly though, no matter how well this one performs in Japan, you have to consider how far we are into the 3DS''s life. We aren't at a point where the 3DS even has two full years left in it. Nintendo even killed the super popular DS after six years, and I don't see them letting the much less successful 3DS go for any longer. The amount of time between a DQ game releasing in Japan, the potential localization announcement, and the localization itself can easily be a two year long series of events. The 3DS may just not be a viable platform in the west by the time a localization could happen, especially when we currently have no idea when Joker 3 is even coming.