I think we need to add a "vocabulary" section to Eyes on Final Fantasy, and define what we classify as a "final boss".

My definition of final boss includes:
-The final boss is capable of creating a "game over" for you. I realize with Yu Yevon you could cast break on all of your characters and end the game, but that doesn't count. The attack must be from the boss itself.
-A final boss requires some form of thought or strategy, either before the battle or in the battle, to defeat it. Selecting "Limit Break" and then "Omnislash" to kill Sephiroth in FF7 thus eliminates him from the category of being a final boss.