I think a remake is the most doable, and perhaps the most fun as well.
First off, there would be a lot of "debugging" that involves actually PLAYING the original to make sure things are just right. That right there is loads of fun, playing the game for "research".
For instance, in MM, there is a surprising amount of detail to even minor things, like what you can do with a Gossip Stone (quite a lot, actually). It would be an excuse to explore the game more deeply, to make sure that things are just right in the remake.