I decided to take a crack at a hardmode, not in WoW, but in Half Life 2: Episode One. The title name comes from the achievement, One Free Bullet, to complete the game firing only one bullet. Rockets, grenades, and stuff fired from my gravity gun is acceptable, and of course my crowbar. The one bullet is to break a lock, not even to kill something. This creates a very strange way of playing a FPS.
My best friends were radiators and explosive barrels. Radiators are great for launching with the gravity gun, a device which can pick up and fire stuff very quickly. Radiators are big, heavy, and have convenient spaces so I can actually see where I am going. Explosive barrels explode. Concrete blocks are also great because they are fairly heavy, but small enough to be easy to aim.
Most of the game wasn't much harder. Generally the hardest fights involve either flying things to shoot with rockets or tripods to shoot with rockets, and neither are affected. The cannon fodder was easily dispatched with thrown objects or the gun of my increasingly clingy companion, Alyx (short version: they saved each other many times, she keeps dropping hints).
Except for the antlion guardian. Think big thing that can throw cars, run fast, and likes to charge into you doing tons of damage. It's hard to kill with bullets. It's harder to kill without. Instead I have to kite it as best I can, keeping sufficient range so that the barrels don't kill me as well. Meanwhile much smaller antlions are flying around trying to attack me. By smaller I mean about half the size of a car. Speaking of which, cars are great for crushing the small ones, while the big one just shoves them right back, harder.
As I've played Half Life I've noticed that it tends to hold the player's hand in terms of learning. It rarely just tosses you into a fight with no clue. Instead you might see someone else use a particular method to kill something. Sometimes they even giver direct advice "shoot for the head" (zombies) or "throw a grenade in the window" (snipers). It sounds more useful in the game, in case that sounded dumb. There's even a training session before one of the boss events, to practice launching and blowing up a bomb.
Why doesn't WoW do this? Why are so many raid boss mechanics new and unexpected, throwing us for a curve when we see them, and requiring retraining of everything? Oh, but it does. It does! We just rarely notice. Next time you run your randoms, watch the boss abilities. Many of them are exactly like raid bosses. The difference is that the heroic does so much less damage that we tend to just ignore it, out-heal it, out-damage it, out-tank it. Then when we hit a raid and our gear can't carry us, suddenly it's a problem.
I can't entirely blame players for failing to learn raid boss mechanics from heroics. For one, there's a time difference. In Half Life I might see an example and then use it a minute later. In WoW you might have weeks between a heroic fight and the similar raid.
But getting back to the heroics, they might also be teaching us bad lessons. How quickly will the poison puddles in AN kill you? It is often healed through. The incentive to move is weakened. Why move out of this puddle when the others don't hurt much? There's no rush. In Half Life you might be shown one enemy, kill it easily, and figure out generally how its done. Then there are five of them, ten of them, and now you can apply those same skills. In WoW it often seems that we're instead shown a trivially weak version of an ability, learn to ignore it, and then get flattened when the 5x stronger version shows up.
Comparisons across genres don't always work. They're not the same game and aren't supposed to be. Still, it's worth thinking about, the different ways to teach a player.