While it's true that having high block rate results in Parry, as a secondary stat, being worse, the best shields now are Towers due to Sheltron and (to an extent) Bulwark. On top of this, block is 1-9% more powerful than Parry atm so if you could've parried instead of blocked, it was better to block anyway. PLD, mitigation-wise, is fine - it only suffers slightly in magic fights compared to the other two. It's biggest problem is the lack of DPS, which is being addressed.