The way I look at it, AV was never supposed to be defeated by just anyone. AV was the ultimate boss of CoP: FFXI. Every FF game has had that ultimate boss fight that was never really intended for the main storyline, it was just a test of dedication and skill. FFVII had the Emerald and Ruby Weapons (part of the story but not necessary fights), FFVIII had Ultima and Omega, FFIX had Osmus and so on and so forth. They were that additional challenge which was supposed to encourage the player to explore everything, obtain every item, gain every skill. Unless you did these things, it was nearly impossible to beat the hardest boss's of the game.

This was the same with Absolute Virtue (and his ToAU equivalent Pandemonium Warden). Unless you were willing to spend the time and effort necessary to obtain the best of the best gear, and learn every possible strategy, you weren't meant to beat them.

If you think about the AV fight as a whole, its kind of like an alliance version Maat. He has his own attacks he does, even when he's mimicing the job you use. But he forces you to play the job with all of your abilities. AV was the same way, but with a small twist. In most situations job's use their 2hr's as emergency measures to survive damaging attacks or take the mob down faster, against AV you had to use the proper 2hr to lock his and keep him from using it again. This meant that linkshells couldn't just go with select jobs they prefer'd to run with.

As an example, you could do entire dynamis runs without some the original 15 jobs and still win (you didn't have to have a brd, drk, mnk, etc). While fighting AV you needed to have all 15 jobs available to lock his 2hr's. That was the point of SE releasing that "hint" video. It was pretty much SE saying, "you're doing it wrong if you only run with certain jobs rather than all of them. If you really want to win, learn how to utilize all of the jobs".

Long Story short: Unless you were willing to accept that every job had a use, AV couldn't be defeated.