As far as I've tested on both PLD and WAR. Both sitting at 247 DEX is the optimal choice, because you can dump a few points into DEX to hit that plateau while using STR/DEX accessories. However if you do not plan to make Gryphonskin stuff you can pretty much just ignore anything regarding DEX cause it will be too much of a manual stat commitment to reach that plateau.

With that said Paladin double dips from the DEX whilst Warrior with similar DEX still hardly see a big jump in Parry difference. Because as Paladin I notice 2-3% increase in Block and 2% increase in Parry which does Add up, top that with using Shield Block I could say like 7 out of 8 hits are a block during that time which could effectively mean 26-30% Dmg reduction (Still haven't bought R1 Shield). Whereas Warriors... they seriously need to borrow something like Keen Edge from Lancers to start seeing real dependable parries, cause as it stands now Featherfoot is our BEST defensive CD...