Shouldn't WoW teach you how to play as you level up?

[Lane]

WoW's never been great at that, although, it used to be better. Ideally, IMO, you should have all your core rotation abilities at a low level so you can get used to mastering them and cooldowns. My own experience is the later in the game I get something the less likely I am to use it because I'm not in the habit of it. There are a lot of 'junk' abilities you get at early levels instead, DPS warrior is particularly bad about this as I kept waiting for key abilities while instead getting things like Shield Slam.

I hated proving grounds, though my only experience with them was briefly in WoD. At the time I didn't realize elemental shaman, which I'd been playing since BC, was in such a god awful place so I struggled to get silver or whatever it was you needed. Things like that are good in theory, but not so much in practice. I felt the same way about mage tower, the same scenario was infinitely easier for some classes/specs than others that had to do the same thing.

These days, bad dungeon groups have been training me to be better. I think I mastered paladin cooldowns more in Pit of Saron this last timewalking than I did even in mage tower.

[Drusin]

Stuns, interrupts, snares, and proper rotations why is it none of these things are introduced to you as you level as individual skill checks?

Because the playerbase wanted faster leveling and Blizz thought the longer leveling process was turning players away

[T-34]

the core problem of wow is people who play this game for 16 years and exepct others to have the same expreince by default

I would like to add that it is equally a core problem in WoW that there are both new players and veteran players that expect and feel entitled to have more experienced and/or skilled players to teach them/carry them.

Luckily the vast majority of people play with people that have a similar approach to the game, so the resulting problems of these conflicting expectations are greatly blown out of proportions.