Let me first say that for me the fight against him was the climax of the game. Plus I was having a major Mohc flashback the entire duration of it- until the end, because the Mohc AI never flaked out on me.
I was a little disappointed when I found an AI bug
with Fyyar that when exploited allowed me to kill him easily.
I'm not going to mention what it is, because frankly, I don't want anyone else to have their fight spoiled by such a silly thing.
You kinda loose believability and immersion when you can get a big bad boss to end up facing away from you and not caring while you pound him with rockets (all by legitimate means, too).