Omega Weapon from FF8 is a completely different creature than Omega from FF5. Omega Weapon wasn't actually that hard, I beat him, and I didn't have any Holy Wars. I had one Hero.

Omega (from FF5) is apparently impossible to kill. Like I said, I didn't get a single attack in before he killed me. My characters were all in the high 60's and each had at least ten job classes mastered.