Quote Originally Posted by TomCatMew View Post
2. Some instant high damage attack. ... Though you cannot parry the flare breathe , you can parry the auto-attack to minimize the damage.

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3. We can see that many mechanics in Fcob are physics damage, such as earthshaker, bennu's straight line AOE. Parry is useful to mitigate those
First, if parry saves you on the 1-2 autoattacks during Flatten+Flare, you were in worse shape than you think. If you didn't have cooldowns up for whatever reason, you have failed somewhere as a tank. If you're referring to the single breaths boss does at points in the rotation: not a big deal. It's a healer check. Stoneskin yourself if you're that paranoid about it.

"Many mechanics" is a really vague way of putting it, and the examples you gave are pretty awful.

Earthshaker - PLD is virtually never going to be hit by this unless you are off-tank or choose to Cover a melee. You will take one hit at worst in P4 if you suck at timing.
Bennu line aoe - What line aoe? Just dodge. If you mean just the Bennu itself, it doesn't hit that hard.

Autoattack crits are largely negligible. Yes T12 boss crits for a ton, that's about the only time it really matters and it's not something you can really control.

Better way of tackling parry vs non-parry is the same way you tackle cooldowns: what am I using them for? Big hits or otherwise healer-intensive moments (adds).

T10
Can parry Critical Rip, adds (except Crackle Hiss)
Cannot parry Charge, Crackle Hiss, or mechanics.

T11
Can parry Resonance, Secondary Head, and Main Head
Cannot parry missiles/gas (doesn't really matter)
Cannot parry adds

T12
Can parry Revelation, Bennu stuff
Cannot parry Flames of Rebirth, Brand passing (doesn't really matter)

T13
Can parry Flatten, Earthshaker (doesn't really matter), Death Sentence, most adds
Cannot parry Flare Breath, Tempest Wing, Akh Morn

Parry is almost useless in 13, and is pretty meh in 10. You can make a case for it in 11 and maybe 12.

Putting a Stoneskin on yourself at opportune times is better than relying on a Parry in most cases.