Could you imagine if they had made you fight some ultimate Jenova after Safer Sephiroth... again?

My deal is that these bosses should instead be the ultimate optional boss. After defeating the big bad, this guy shows up so you FEEL that you HAVE to beat him or the game over is approaching. But then if you lose, there is no game over, you still see the ending scenes and credits. But beating this optional boss could alter the ending you see.