Yes, I've fought Faust. I thought he was going to be incredibly difficult, but I beat him on my first try. He counterattacks with spells, so the easy way to beat him is to have two of your characters defend, and just have your strongest character pound his face in. He has the lowest defense of any enemy in the game (aside from maybe the Berserker in the Land of Gigantos), and additions can do upwards of 5000 points of damage to him making the battle a mere 6 attacks long for you. I honestly thought he'd be harder than that.

I forgot about the Divine Dragon and the Divine Dragon Spirit. Those bosses were also damn hard. So was the disc 1 boss guy who's name escapes me at the moment. He was the purple dragoon guy. Man that guy was tough.

Another tough boss was that Grand Jewel boss in Kadessa. He's a lot like the final boss in that you cannot use your dragoon forms.