Here's a more dynamic version that doesn't give armor bonuses, but significantly improves Evasion and defend. I should mention it is compatible with the original Agility plus (which would make agility extremely formidable).
in Game battler 3:
defending against physical attacks
around line 55-65
# Guard correction ==> modified by shintashi
if self.guarding?
mu = (self.agi / attacker.dex) * (self.agi / attacker.dex)
self.damage /= (2 + mu)
end
end
around line 65-75
# Second hit detection ==> modified by shintashi
mu = (self.agi / attacker.dex) * (self.agi / attacker.dex)
eva = 8 * mu + self.eva
Defending against magic and skills
around lines 140-150 # Guard correction ==> modified by shintashi
if self.guarding?
mu = (self.agi / user.dex) * (self.agi / user.dex)
self.damage /= (2 + mu)
end
end
and around lines 150-165
# Second hit detection
mu = (self.agi / user.dex) * (self.agi / user.dex)
eva = 8 * mu + self.eva
I created a fencer and with a 95 Agility he was able to dodge ghosts approximately 50% of the time. This also increases damage reduction when doing "defend" as your main action. If your agility were say 50% higher than the opponent, you might take 1/4.25 rather than 1/2 damage.