Cataclysm was a rough time for many players who had developed very bad dungeon habits in Wrath of the Lich King. The group up and AoE model for trash, often taking more than one pull at a time, didn't translate to the new dungeons and the new healing model. This adjustment to CCing, paying attention to enemy abilities, and otherwise playing well was never going to last, however, and for the most part my guildmates have already returned to killing everything at once in heroic dungeons because 359 gear allows that.
But if 359 gear enables the group up and AoE strategy in heroics, what level of gear is required to enable that strategy in normal?
Let's look at the abilities from normal and heroic trash. Here I'm intentionally choosing some of the most deadly trash mobs available in level 85 dungeons. These mobs aren't necessarily that dangerous if handled correctly, but will easily kill individuals or groups if their abilities are ignored.
Ascendant Waterlashers have wiped more than one group I've been in because their front cone has been facing the group. This cone lasts 4 seconds and deals damage every 0.25 seconds. On normal it averages 1500 damage per tick, on heroic it averages 4000 damage per tick.
Temple Shadowlancers channel Pact of Darkness doing high damage in melee range, and often killing off melee dps who do not interrupt it while also putting a strain on tank healing. Pact is channeled and deals damage every 1 second. On normal the average damage is 4500, on heroic it is 18000.
The penalty for not dealing with an ability correctly on normal is in the range of 27000 damage to a single character or up to 96000 damage spread around the group. On heroic it is instead over 108000 to an individual or upwards of 256000 damage divided among the group.
Not all heroic versus normal mobs have such extreme differences. In many cases, the damage difference seems to be around 50%, but spells that you are supposed to avoid or play around are often much higher. All of this brings us to the fact that if you walk into normal with some 333 gear and some 346 gear then there is little reason to CC trash or react to abilities. Failing to interrupt a spell that an enemy is casting doesn't mean very much. Facing the enemies the right way doesn't mean very much. Targeting the right enemy first or burning down a dangerous enemy doesn't mean very much. The gear you can get from soloing is adequate to group up and AoE in normal instances.
Equally important are the boss abilities. On normal, General Umbriss' Blitz deals 30k, on heroic is deals 100k. On normal, Erudax's Shadow Gale deals 3k on the first tick, increasing to 30k by the last one for a total of 165k, on heroic it deals 10k on the first tick, increasing to 100k for a total of 550k. On normal failure to dispel Anhuur's Divine Reckoning means 15k damage, on heroic it means 45k. It is hard to directly compare bosses outside of level 85 dungeons because you encounter them at different levels, but the numbers are still telling. The rocks High Priestess Azil throws on normal deal only 35k damage, which is survivable for a level 82 character. On heroic they deal 400k damage which is not survivable for anyone. Ozruk's Shatter is similar, dealing only 30k on normal - a hit you would expect your tank to simply take - and 150k on heroic - an instant fatality to new geared heroic characters. With the new healing system, I often see healers saying, "I can't heal stupid." In normal dungeons, you can.
When the developers say that players who are having trouble with heroic difficulty may want to try normal difficulty to learn the fights, they are ignoring the fact that you can't really learn many of these fights on normal. Learning only happens when there is a motivation for it. When your tank gets killed by Pistol Barrage the first time you face Godfrey, you ask questions like, "Can you move out of that ability or should you use a cooldown? Will he move to keep facing you when he's casting or can you escape without taking any damage at all?" If we imagined a level 85 normal version of Shadowfang Keep, the tank would be taking manageable damage while standing in the barrage. Those questions may never get asked, and while the healer would walk out of the fight saying that it seemed like a lot of damage, a win would be quite possible while ignoring all the mechanics. If you never have to ask questions like that to win, then you never learn to ask questions like that when you aren't winning. What is going wrong in heroics becomes a mystery - it seems like you just can't heal enough.
You don't learn Altairus' upwind/downwind ability when you can heal the fight with the haste penalty. You don't learn Throngus' Phalanx ability when there is no penalty for standing in front of him and your healer isn't in danger of running out of mana. In some cases key abilities don't even exist on normal. Normal Ozruk doesn't cast Paralyze, normal Beauty pulls separately from her pups, normal Setesh doesn't have attackable portals.
The longer you stay in normal dungeons, the more gear you get, the easier they become. But the bad habits that people form in normal dungeons are going to do more harm than the gear they collect can do good. This is why we see healers complaining about getting kicked from groups after the dps make unhealable mistakes. After enough experience in normals, "unhealable" leaves your head as a concept.
Tomorrow I'm going to look at the solution that the developers are implementing in 4.0.6 to make normal dungeons more attractive - increased Justice Point rewards - and what effects we should realistically expect from that change.