FF VI is in the running for best game of all time, any platform, any genre, and it's easily right up there with any of the later FF titles.
Well balanced battle and advancement system, epic, engaging plot without a lot of the wonky stuff of later ones, the ability to actually pick and chose the party you want rather than being stuck with a loser protagonist in your party that you don't even like, easily the best soundtrack of any video game ever (Dancing Mad, Maria and Draco, Terra's Theme, and the end theme montage of 15 different character themes is a tour de force), and it has two strong, interesting, likable female leads.
For all the love that FF VII gets (I assume it's because of the FMVs, but how anybody could like Cloud as a protagonist is beyond me), I will quote one guy I know to voice the opinion of every serious long-term Final Fantasy fan I know: "They should just do a full-on current-gen remake of FF VI and call it done. That's what we're all really waiting for, and nothing is going to beat that."
Not that I'd turn my nose up at an iOS upgrade, so long as it isn't dumbed down, but taking the same game and upgrading it so the whole thing looked like the Amano-styled FMV segments for the PS1 release would be pretty much the ultimate JRPG. The technology exists, it's just a matter of budget.
That said, if they do a remake and don't use Amano's designs (like the character art in the FF IV remake), I'm getting the torches.