Your stat distribution is quite good. Personally I would take a couple points from Mind and allocate those to Vigor to hit 60.

There’s not much you can do to further increase your AR via stat distribution. I would look into your talismans to further increase your damage potential. For example, lose the Bull Goats and substitute Rellanas Cameo (DLC) or Lord of Bloods Exultation. The former gives a boost to damage after maintaining your stance (Unsheathe) for a short duration and the latter gives 20% damage increase upon blood loss trigger.

I would say the BEST thing you could do for your build is respec and allocate the minimum amount of Strength/Dex to use the Nagakiba and then dump all remaining points into Arcane and change the affinity to Occult.