I don't really think they'll ever actually bother to officially release Mother 3 outside of Japan, and to be honest I don't think I want them to either. It seems like they would have to absolutely ravage that game to avoid rights issues with the music, not to mention how much they might need to change in localization. I can see the Magypsies causing an uproar on both sides of America's (and likely other nations') political spectrum for different reasons, and they are quite important to the plot. I would want an international Mother 3 release to be as unaltered as possible, and that's a longshot. As much as I love the game and despite the fact that it's one of my favorite games of all time and that I would love for it to reach a wider audience, Nintendo is saving itself a lot of headaches and hassle. I feel like the fan translation would end up being far more faithful than whatever Nintendo would churn out, and since Nintendo likely isn't just going to use a fan translation in their official release for myriad reasons, their not cracking down on the fan translation and letting non-Japanese fans experience the game in this roundabout way is as close to an ideal situation as is possible. The intent of the art is maintained as closely as possible this way, and that's the most important thing in my eyes.
We've already had re-releases of Mother and Mother 2/EarthBound 0 and EarthBound in recent years, so that's taken care of. As far as a remake goes, I am not altogether interested unless it was extremely faithful and kept all the idiosyncrasies. But even then, I neither need nor very much want a remake. The originals are fine as they are.
Just as Shigesato Itoi is content to leave Mother 3 as the final Mother game, so too am I content with his decision. I'm not particularly fond of the concept of franchises on a base level. It's nice to have a sequel to a game, a movie, or whatever else it is that you like, but as a writer I tend to feel that a work shouldn't be created unless there's a purpose, a drive, and a love for the work you're creating. This applies doubly so to a successive work/sequel, and it continues to multiply for each work in a series thereafter. If Mr. Itoi doesn't have another Mother game in him, then it is what it is, and I am none too interested in anyone else taking the reins considering how baked he is into the framework of the series. We have the 3 games through one means or another, and that's more than good enough for me.
I feel NoUsernameHere has the right of it when they say:
We may never see a new entry in the franchise again, but as long as the passion and the love for the franchise is there, in my eyes, it has a future. They say when a person dies, on average, they're remembered for about 70-something years after their death. This is called a second death. Mother will never truly "die" until it's no longer remembered by anyone. Those are my thoughts, anyway.