In something like, say... Assassin's Creed, for example, you're plainly told what everything does, as you're able to do it, and given, immediately after learning what to do, something you have to do with it. WoW doesn't do that. You have to want to know what to do. Unoptimal/improper play is rewarded and acceptable until the endgame, where it isn't. Almost everything in your toolset is unimportant and unprovoked until then. There's a big gap there, where the game doesn't actively teach you how to play it. It just says "Stuff is here, it does some stuff probably. Figure it out."
In that Angry Birds example, it's pretty plainly clear. Pull band, hit pigs, break things. When you get a new bird type, it immediately shows you a visual example of what that thing does, and how to use it, and how it applies to the game. Again, WoW doesn't do anything of the sort.
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