Fenrir.Nightfyre said:
Raising critrate means more opportunities for Razed Ruins, Crit Atk Bonus, and AF3 feet to proc. That's a 45% damage bonus on any crit (feet+2 are 10%, not sure if +1 are same or less), only 5% from the 50% cap. Voracious Violet, cruor buffs + abyssites, 2hander bonus, meat/pizza, any attack buffs you may have (Stalwart's sup) along with debuffs on the mob (Dia), and potentially Berserk mean pDIF will be very high, if not capped. If it's high, the attack won't benefit all your crits due to the way crits cap vs normal attacks, and more than half your hits will be crits. 30% Razed Ruins, 20% capped dDEX, 4% merits, 15-20% from the WS itself per Robonosto's data, then any gear... A conservative estimate puts 69% of your RR hits as crits before gear. If it's capped, attack is obviously worthless.
I do understand the value of crits in Abyssea, I have +48% crit dmg in my current ws set (same as you mentioned + 3 from backpiece) to take advantage of it. From my experience however, crit rate tends to cap out (taper off?) around 75~%. I've seen it slightly higher or lower, but never considerably outside of that range.
Current crit plus is:
5 - base rate
15 - dDex (conservative vs your 20% estimate)
30 - RRuin
4 - merit
3 - grip
3 - head
15 - RRush base (conservative vs your 20% estimate)
=
75% crit rate, 85% using your estimates. That would suggest that GH atma would put me at 95-100% crit though, which was not the case when I played around with it.
As for the attack, while I'm typically capped against the standard mobs, due to my setup (war mnk thf brd whm) I'm not certain I consistently cap with Dia II alone since we default to double march. Without knowing the stats of Abyssea mobs, I simply decided to err on the side of caution since I felt I had crit capped.
Of course it's possible that my data was wrong, and crit rate does not cap at all. There's currently some testing going on @bg on the topic, if I'm wrong I'll happily go back to Zahak's.
I'd much rather be optimal than be "right".
Update: Derped on an atma name, corrected it now. From the longer duration parses being posted, it looks like 75~% is pretty accurate. There is an outlier parse of a few hundred swings that goes higher with Innin, but the same player posted a longer (7.5k swings) parse that falls back in line with the 75~% cap idea. Unless something is revealed that shows ja/ws can break 75% consistently, I still believe Grim Cuirass is superior to Zahak's for my build.