Are we playing the same game? I just set up my gambits once at the start and watched the game beat itself.
Realistically anything not on the NES is just a whole different level, the only question is picking between 1,2 and 3. FF1 sticks out in my head, but I don't really have anything to back it up with.
Of the post NES era I would say that FF4 DS is the most difficult. Difficult in a good way that actually makes you think and strategize.