Baldur's Gate : The Sword Coast Chronicles : NWN2 Persistent World

Flourish is hardcoded, so your test results should still be valid.

Flourish has no requirements. It works armoured, unarmoured, off-hand, no off-hand, piercing weapon, no piercing weapon - it works with anything.

I thought elaborate parry is for dex fighter to buff the AC which close to the heavy armor fighter. The fighter with full plate should not so dexterity.

I suggest the feat can limit by the actual dex bonus, so that the AC bonus will depend on armor type. Elf CoCL keep remain their unique dexterity heavy armor characteristic. DEX unarmor also can buff their AC close to heavy armor & shield.

10 levels of an otherwise rubbish prc is extreme, considering how easy it is to get that kind of AC with a Man At Arms build without even resorting to entropium.