True, VIII did have limit breaks. I don't think that makes the characters more unique vs what's presented in VI, but it certainly was useful. You know, I think that VI did have some sort of overdrive attacks. You had to be under like 10% HP to use them or something, so I never really did, because I heal faster than that, but they were there.

The speciatly attacks of 6 were a part of the battle system, but they were also a part of character upgrades as well. This type of thing gets into a grey area. Most of the characters, you're right, were fairly inefficient in using these late in the game, but Sabin's attacks, and Edgar's too were still powerful at the end. Although it was still easier to use Ultima as you said. That's pretty much all I did the entire trip through Kefka's tower. That, and attach no encounters.