I think they should really make parry better, especially since it's one of the main stats for DRK due to their lack of block and having no hp boost like the warrior does.
I haven't leveled one up yet but I can already see that they're not on par in terms of a Paladin's defense, and not entirely up to a warrior either now.

Paladins have a shield so on top of parrying they can also block, in addition to have some of the strongests mitigations around.
Warriors can only parry but with the expansions they have far more mitigation chances with Raw Intuition and have a slight Parry boost thanks to the new defiance. But even without them, they have a constant 20% healing and 25% hp boost.
Dark Knights have dmg reduction but can't block. They have some dmg mitigation skills and a parry boost, but no healing or hp boosts. They can dish out damage but they're not as strong as a warrior in my opinion.

I think parry should be reworked indeed, especially in help for DRK.
Maybe on top of 20% dmg reduction they could have a boost on parry and the additional chance of parrying magic (like others have suggested): they would become excellent magic breakers and would make them more required on fights where magic damage is more constant.