Worst things in FF12 to me:

Chest randomness... too many random factors.. pick one or two.

Quickening randomness... For my most recent playthrough, I wanted to do a little powerleveling. Unless some unforeseen factor is randomizing the damage, my quickenings on the werewolves in giza are very flaky at best. I've did one white whorl, a 1 hitter, that killed the werewolf doing 3200 damage.... and next time on the other werewolf, did a 5 hit combo with 2 white whorls and 3 red spirals that only did 1700 damage. I've seen two red spirals(hope im remembering this right) hit for 1500-2000 damage, while i've seen two of them hit for 300 damage.

Summons/Esper weakness - the overall strength of the Espers/Summons.

That's about it for my memory for now.
and related to first post.... Vaan's abs are fine I guess, never paid that much attention to them.