SNES hacking would be significantly different from Wii hacking. Having done several minor mods/translation attempts of SNES games a few years ago, I can tell you, in theory at least, it should be much easier to access the correct portions of the game and alter them since you won't need to individually rebuilt indexes and pointer tables.
That said, it's still not a walk in the park, especially because you'll still have to modify graphics, translate the game, bug test, and do quite a bit of assembly hacking...