(SPOILER)FFVI. The Empire Gesthal.
Justice Syaoran Hammerhand Tavrobel, concurrence in the case Jammi v. Boko, 2.718 U.S. 3.14 (2008).
To be perfectly fair, it might have been an easier time justifying your point by using FFIV as precedent. Though characters in that game have classes, there was never a doubt that it was not a class system due to the rigid way the game forced characters to progress; FFIX uses the same scheme and method. FFI does have a class system, however, it is not as able to give free reign due to:
A) forced selection at the beginning
B) choice of evolution at the Castle in the Sky
Technically, you do get to choose, and you are able to evolve into a higher class if you wish to do so. There's no event in the game that forces you to, unlike FFIX's "silence Dagger" portion, and the obvious and clear superiority of Eiko as both Summoner and White Mage. I approve of the final decision, but not the logic for it.