I think it's exactly the thing that could and did cause the frustration. Yes, paladin in mid 30th is hard fight for duergar or even pretty much any evil. But he did have the chance vs solo you. Yes, it would require good amount of luck and still would be very dangerous, but it would be possible (all bashes could land, your aura could fall..). Healer makes the fight just dumb waste of time. He can't kill you no matter what and can easily die after one mistake on his part. Who the hell would fight at those conditions? And why to play if you can't get interesting fight with at least some chance to win?