Any hopes that Mother 3 was in the process of being translated in English have just had their hopes dashed by Nintendo of America Treehouse Localization Producer/Manager Nate Bihldorff. In an interview with Planet GameCube, Bihldorff exclaims that he "wouldn't look forward to [a Mother 3 translation] in the immediate future," adding that none of the writers are currently working on one, though maybe some of the translators that do not work for him may be "in discussion."
It has been over seven months since the title was released in Japan, and in development for years prior -- if Nintendo was to bring the title over, the process would have already begun. That it would be a sure-fire hit, with a built-in audience of rabid fans, is just another piece to the confusing puzzle: why would Nintendo, as a for-profit business, not spend the time and effort to bring the title over?
The fan translation for Mother 3 has been ongoing since its launch.