Gamasutra has reported that at GDC 2010, Blizzard EVP of Game Design Rob Pardo described a number of the design concepts behind Blizzard's games.
I'm going to take a contrarian and admittedly somewhat cynical view of these design principles. At the risk of some exaggeration to illustrate a point:
Gameplay First = Dumb It Down
Just like every other corporate developer of multi-bazillion-dollar game product, In any contest between immersion/lore-based play and rules-based play, only rules-based play may ever be allowed to win. No one cares about content that stimulates hearts and minds; emotional and intellectual activity are invalid forms of play that must be avoided at all costs in favor of simple action. Any producer whose studio is making a $10M+ game is expected to lie by saying that they understand the IP and will be treating it with respect in their game -- there's no harm done since everyone knows they don't really mean it.
Easy to Learn, Difficult to Master = Dumb It Down (But Never Admit It)
Individuals are irrelevant, so you can make the gameplay as mind-numbingly simple as possible as long as you let players do things with and to each other. You get "hardcore" for free simply by allowing multiple players to do some things together, so use that as a selling point in your PR... even if the reality is that you will be spending enormous amounts of time watching for and nerfing the many exploits that emerge only in massively multiplayer games.
Make Everything Overpowered = Extremier! To the Max!
Gamers are easily distracted by lots of flashy lights and loud noises centered on their character. Throw lots of flashbang art and audio at them while stroking their senses of self-importance, and players will never notice there's no substance behind the repetitive rules-based action. What could possibly be wrong with telling gamers that they are godlets whose every whim ought to be catered to?
Play Don't Tell = TL;DR
Everyone knows gamers are illiterate juveniles, so clearly there needs to be an iron law that says no piece of text can ever be longer than 512 characters. Design every part of the game as though every player suffers from terminal levels of Attention Deficit Hyperactivity Disorder, and there will some people who will actually pay you to play such a game. And as a bonus, there's no need to hire anyone who is capable of crafting sentences that express meaningful thoughts -- writers would just get in the way of Adrenaline-Pumping Action!!
Make It A Bonus = Mine! Mine! Mine!
You must never, ever be perceived as taking something away from players, who quite naturally believe they own the individual character they play, the "physical" assets and innate attributes of that character, the class-determined abilities obtained for that character through long grindy leveling, and every area in which that character has leveled up. Players must be encouraged to hold that legally false belief of ownership even if it means tolerating massive amounts of RMT and drama over nerfs, because promoting a feeling of investment (i.e., playing with a player's psychology) is how you condition players not to cancel their subscriptions.
Obviously there's some validity to the design notions that Rob Pardo has talked about or World of Warcraft wouldn't as be as successful as it has been until recently. And I don't object to people enjoying what WoW offers -- if people like that sort of thing as entertainment, it's OK that there are games like WoW to satisfy those playstyle interests.
But to go beyond that to suggest that the design principles behind WoW should be used to create other such games? No, thanks. Game developers are already hyper-focusing on simplification of action. That trend doesn't need to be assisted any further.
Design concepts like WoW's that are focused on delivering simple action don't work for other playstyle preferences, such as simulation/exploration play or story/roleplaying play. And they won't lead to games that are equally satisfying to gamers for whom those playstyles are primary.
For those, we need different design concepts... and probably a different kind of game developer. To the extent that Pardo himself acknowledged this, I agree with him.
But is that even possible any longer? Is there anyone willing and able to make big standalone games that are consciously designed to appeal as much to the hearts and brains of gamers as to their hands and glands?