The only change I see necessary IMO would be to make Blood Weapon usable during Grit, but remove the attack speed bonus while in Grit (ergo, it would only generate MP), and to give Delirium a slashing debuff under Dark Arts (so it isn't outclassed by MNK and DRK can serve a practical purpose if there isn't a NIN or WAR in the party)

Other than that I feel most things are pretty solid. I haven't really had trouble with the class after 50; it generates hate well, and has a fairly potent lifesteal, my only gripe is its synergy with the party (which I feel can be fixed rather easily)