Depends on how profitable (remember Atlus is a business) the game will be. They've released titles in Japan that haven't reached here in US (i.e. Devil Summoner, Princess Crown (My friend is eagerly waiting to be translated cause he can't understand the story in the walkthroughs. :: )). I'm surprised they brought over Hammerin' Hero (though nothing wrong with a platformer) instead one of the their popular niche titles, but the DS is outselling the PSP and makes it the "better" bet.
Getting hungry...will finish thought process later.