WoW does not currently teach players. It just throw them at bad situations and expect them to find the way out.

There is nothing, in game, that tells you what you are doing wrong in an encounter. Nothing that tells you what you are doing wrong in your rotation. No resource to tell you that you are doing subpar damage, lack healing power or power regen, are not mitigating enough damage, whatever, for your gear level. Nothing that tells you if your gear packs the right stats, or if you have the right (or right quality) gems and enchants.

Not only the game does not teach players, they often have no in-game way to see if they are good players or not, or to know how to get better. Unless the player is a proficient theorycrafter, he will be forced to use external information sources to get better - and an awfully large amount of players never take that step.

The game needs better ways to show players how good they really are and teach them how to better themselves. For example:

- Target dummies that not only tell the players their sustained DPS/HPS, but also for which tiers of content that performance is enough.

- Mini-games that simulate typical raid situations and boss attacks, for each role, and tell the player what he did wrong, and what he should be doing to improve.

- A LFD tool that actually evaluates the gear's stats for the selected role or roles, warn about bad or useless gear, gems, or enchants, and prevents players from actually queuing for a random group in a given role if they don't have the required stats to adequately perform the role.

- Perhaps even an integrated DBM/GTFO that is forced on for random groups, but can be turned off if the player queue as part of a full group. After all, those resources are readily available anyway, and Blizzard never did anything to prevent them from working.

Anything that teaches players how they can improve themselves (and prevents players that are not actually ready for a given content from queuing for a random group for said content) should help - and the game should be always ready to point players to those resources as needed.