I am going to have to second this. Problem solving (a.k.a. figuring stuff out), is one of the, if not the most important skill you can have in life. Applying it in video games is great. Especially considerig how many kids play them as it teaches them a valuable life skill and mentality. People giving up as soon as things get challenging will never get far in life.
Though that makes it sound like problem solving is something new to game. The fact is that problem solving exists in every single (serious) game ever createt do different extents and degrees.
- - - Updated - - -
I do agree that WoW is not that great at teaching people the core of their game. Actually, scratch that, WoW is great at learning players the mechanics, but players still do not learn them since they have no incentive to learn.
This is for two simple reasons, leveling is too fast and too easy. You level up so fast that new players dont have time to let the new abilities sink in, and leveling up is so easy that you do not actually have to learn what your abilities do and what are the most effective. Which means you can spend the entire leveling process completely mindless and doing some totally wrong, and never even notice it. The core is there, when you level up it pops up "You have learned a new spell!", it comes out on your action bar automatically and the tooltip says exactly what it does. The problem is that the player has no need to actually learn what the spell does or use it, as whatever he does he will still level up properly.
The entire leveling process now is just meaningless. Just a pointless grind.
I see proving grounds as a step in a direction away from that, trying to provide challenging content. If the content does not challenge you, you do not learn anything.
And yeah, of course a game like Angry Birds is more plain and linear, as it in itself is simply a platform game. It is not a large complex gameworld with different types of classes, mechanics and challenges. It is a simple game with short levels to complete. Still, the basics is the same as WoW. You get told about your toolkit and about the challenges you face. The difference is that both the toolkit and challenges for example are more challenging in WoW than angry birds (duh) as one is designed for a gaming platform and the other for cellphones. That for sure does not mean that WoW is more challenging than other PC games. Dont get me wrong at that.