I had a little idea to buff agility builds, what if enemies debuffed with accuracy down could miss, regardless of the "cannot miss" property in some attacks? This could also work with evasion up.
This could be implemented in different ways: attacks whose "cannot miss" property was negated could have a fixed chance to miss when the appropriate buffs/debuffs are in action, or they could instead behave as default accuracy attacks. Either way, this would be a very deserved buff to both agility and the evasion up/acc down abilities.