For maining tank since 2.0, What I can tell is tanking in this game became easier and easier. No more patrolling mobs to be aware of (like giant tomberies in the first Wanderer Palace), nothing dangerous in the environment.
Just a straight corridor with almost everytime packs of 3 mobs.
The "I dont know the dungeon does not apply verywell as the same pattern is everywhere".
More of the times, bad tanks I came accros are those who don't even look at the party composition.
Simple exemple : If I get grouped with a Ninja and a Monk, that means few aoe to burn huge packs. In such a case, pulling everything is useless, because I will get hit harder for a while, preventing the Healers to dps. In such a case, simply pulling step by step while marking a short pause to allows the monk to refresh his GL stacks is way more effective.
The first huge pull in BWall, I see it often, but few tanks can actually manage it well.