Eh, they were popular because of the attachment to the Final Fantasy brand.
So, what S-E needs to do is bring over the remakes, but as some branded Final Fantasy game, like before. That should do the trick. Of course, I don't see it happening, but it's a nice thought.
On second thought, maybe that wouldn't even work. Final Fantasy doesn't have quite the cachet that it did a few years ago, so it might not achieve instant success just on the association with the series. How is Four Warriors of Light doing?