Thirtyish minutes is not so bad for a regular run. A hint for the final boss, save your GCD defence buffs for when he does "everybody's grudge". The move is telegraphed by the announcement "X Enemies Appear". When you see that, put up your buff. You can use Rampart or Foresight for 2 or 3 stacks and Sentinel or Hallowed ground if the stacks get bigger or at the end when a party will sometimes ignore the adds completely to push the final zerg.