Well the game does exist by any measure. It's surprisingly brutal, perhaps even more so than your Rebirth hack JCE. And there are a few neat touches to make it more inline with every other RPG (except for respawning enemies and treasure chests, there are none of those so you need to make your blows and Gil count) The character graphics... are quite clearly RPG Maker, but for what its worth I would have paid 5 dollars for it. There are a few glitches with it though. You can de-quip your guests (which is almost a necessity due to how fragile Benjamin is) and this can lead to Kaeli giving you her Axe after you've already taken it from her...
Combat seems more strategic with Status Ailments (of which none existed in the original really against foes) being imperative and magic is learned by leveling up rather than just being taken.
I made it through Level Forest, forgot to save went to a Battlefield, and got into an unwinnable encounter. And I apparently had not saved since the start... whoops. I'll revisit it another day, but it's really not that bad. I can see though why Square rejected it though, if they had done up the environment and the character graphics a bit more I think they could have made it work, but alas. They didn't seem to put as much effort into it as they should have.
Again, still worth 5 dollars, so they can keep what I sent them through Paypal.
Only way I would remake FFMQ would be on FFIV's engine. But... there's so much there that could go wrong. Enemy Sprites not changing would be one thing (three sprites for each enemy, no thanks!) and the action portions of the game don't work by default in FFIV unless a Lot of custom coding is done to the overworld which I think is beyond anyone's ken as of now.