He's got Obroan Relics, he doesn't want Arkanian from DF/DP... The only upgrade is Dread Forged.
If nothing else you could run 55HMs to get the daily and weekly bonuses. That would put you in 72 and 78 pieces all around, if slowly. You can also get a full set of 69 gearing from completing Oricon and doing one weekly, plus the relics for completing DF and DP the first time.
If you do really want to improve your tactics there are good videos out there on how to tank. You're the main tank as you said, so take yourself to that next level.