There are two major types of video games. There are games where discovering the proper strategy is the difficult aspect and games where enacting the proper strategy is the difficult aspect. Of course, it's more of a spectrum than two absolutes, but I'll provide games as close to the absolute as I can.
First, consider the game 3 in Three. If you've never heard of it, I suggest taking a look, though getting it running on a modern computer is quite a hassle. It's basically a logic game, with around 50 puzzles. In nearly every single one, if you can answer the logic puzzle, you're done. For example, in one puzzle, called Level 8, it gives you a set of clues, each of which leads to a word ending in the sound -ate. For example, "to blow up" would be "inflate." The difficulty is in discovering what to do; There's zero difficulty in typing in the correct word.
On the opposite end, consider Ikaruga. That's a video showing exactly how to do the 5th level. With that information, do you think you could pick up a copy of the game and copy what he did?
Games where solving the puzzle is more challenging than performing the actions were much more popular when games were new. The issue is that in the modern day, with the advent of communication and the internet, the entire challenge of the game can be bypassed. To be fair, people who truly enjoy the puzzle-solving aspect will solve the game on their own with no help, and that's all well and good. However, as soon as one person has solved the puzzle, all information necessary to perfect the game is available.
World of Warcraft sits on a very interesting line in this regard. While PvP is necessarily the latter, PvE is effectively the highest level of competition in the former. The entire challenge is solving the 'puzzle' of the boss fight. Once it's been solved, once you have a strategy, the fight is repeatable. If you post a video of a world first kill, there are usually dozens of copycats very soon afterward. Notable exceptions have been Firefighter and Yogg-0.
This is why people say WoW doesn't take any skill. Because once the strategy is well known, the puzzle has been solved and anyone remotely competent can copy the solution. It's the root of the attempt cap- It's supposed to better showcase skill when all it really does is forces people to spend more time solving the puzzle in simulations rather than in attempts. It's supposed to separate out bads by preventing them from finishing the boss, but all it really does is focus a lens on who does and does not have the right strategy.
I personally despise the attempt cap system. I hate it abjectly. I feel that fights as complex and difficult as the original Firefighter or Yogg-0 cannot coexist with an attempt-capped system, and as such the system will inherently lower the top-end of the game. But if fights were designed where the challenge was in performing the boss fight rather than in discovering the strategy, maybe attempt caps could finally go away.
Maybe I'm just dreaming of the world I want rather than the best course of action for WoW itself. Who knows.