Bort, is your DD full str based with med armor and the leg. battle hardened feats? Because almost all DD builds are sturdier dmg wise than this one, to be honest.
Edit: forgot to mention to not drop parry. Edit #2: DD crit immune is soooooo slow movement that I'd still take parry. You can't get anywhere with it on and it's just a waste of time to repeatedly turn it off and on just because you dropped it.
Didn't have the Legendary Battle Hardened feats on mine, no - didn't pump dex either though (beyond base 14), and used medium armor and a shield, not robes, so you're right - my immunities are better.
Yes i was thinking of ditching Parry for Concentration. If you can put a few points into Concentration by lowering others a little (as Stryker suggested) and find some gear with Concentration on, that should be enough.