I had something occur to me last night after browsing BG, suggesting "Did you try using the Chrono Cross?" as a lolsolution to beating AV. Then I started thinking back through all the SE games I've played, trying to come up with other games where there was a difficult *and* gimmick-oriented fight to deal with. I figured maybe there was someone in common between Chrono Cross and FFXI that might explain why we have this stupid mob with his sooper sekrit weakness.
So, I checked GameFAQs for the battle programmers on Chrono Cross, and surprise surprise...it's Hiromichi Tanaka. Checking Wikipedia for his other game credits, I see two other games with gimmick battles - Xenogears and Threads of Fate.
In thinking about the battles in the main FF line with stuff like Omega Weapon and Ruby Weapon and Hell Wyrm whatnot, they're all difficult to a certain extent, sure, but they don't require you to, say, use spells in a particular order that is minimally suggested by subtle hints elsewhere in the game, or carefully select your party based on Chu-Chu's "fuel consumption" (or lack thereof).
I didn't play Threads of Fate long enough to really say I am substantially aware of it, but less than an hour in, having to XP grind just to get enough MP to use a fire spell enough times to make my way through a long cavern of ice that re-forms after a few seconds. I imagine it only got worse from that point onward.
So, this may essentially be a battle we can't win, in terms of bringing reason to the argument. The man seems to delight in his puzzles of frivolity.