Gevlon estimates that there are 1 to 2 million morons playing World of Warcraft, and concludes with a postscriptum: "PS: of course there are not just good players and M&S, there are casuals too, who just play for the content. But they are a minority and I doubt if Blizzard would be happy if they would only get the $15 of good players and casuals." Wait a minute, a player is either a good player, a moron, or a casual? What about the average player?
If you sort a population by any measurable criteria, like their height, their IQ, or how talented they are in a video game, you will almost always get a curve which is so universal that it is called a normal distribution, also known as Gaussian distribution or bell curve. It basically tells you that most people are of average height, IQ, or video game talent, and that both extremely (small, dumb, bad player) and extremely (tall, clever, good player) populations are very small. The curve is also symmetrical, meaning the number of people at the both extremes are the same, e.g. exactly as many people are morons with an IQ lower than 70 than there are brilliant people with an IQ higher than 130.
Now the bell curve centers around a natural average. For IQs the curve is normalized, so that the average IQ is by definition 100. Other natural distributions don't have such a normalization, and people making subjective judgement cutoff points between good, average, and bad might not place them symmetrically. If you have an IQ of 130 and believe that anybody less clever than you is "a moron", you end up living in a world where 97.5% of people are "morons" in your eyes. If you not only have an IQ of 130, but also understand what a normal distribution is, and use a scientifically accurate standard definition of "moron" being less than IQ of 70, suddenly there are only 2.5% of "moron" in the world, and 95% of average people between 70 and 130.
If you say that 1 million "morons" are playing World of Warcraft, and you fairly put your cutoff points symmetrically, saying that a "moron" is as far away from the average as the "good player", you also get 1 million good players. And you get 10 million average players. You can put the cutoff points somewhere else, but in any reasonable definition of "good", "bad", and "average", you will always get a much bigger population of average players than of good or bad ones.
Ignoring the existence of the average is what Gevlon would call an "ape subroutine", a social mechanism where people tend to think in terms of "us and them", or "black and white". It is rather typical of certain WoW players, who tend to define "good player" as "playing as good as me", and then use some sort of insult as term for "everybody not playing quite as good as me". It is an extremely social reflex of status thinking to pretend that there are "good players" and "bad players", with nothing in between. Very few people want to admit they are average (For the record: I'm a pretty average WoW player, as far as I can measure that.). Thus you get that endless stream of comments on various blogs and forums on how Blizzard is catering towards "the dumb", or "the lowest common denominator", or "the morons and slackers".
Blizzard, who have much better data than we have, and better business sense, probably realize that there are very few really dumb players in World of Warcraft, and very few exceptionally good players. The huge majority of WoW players is average. And the only design decision which makes business sense is to make World of Warcraft reasonably challenging but doable for the average player. Depending on how large or narrow you define average, between 50% and 95% of players are average. That is where the bulk of their income is, and World of Warcraft *has to* be fun, that is challenging but doable, for that bulk of players.
And that is exactly what they do. For example Gevlon cites the "cloth geared, ungemmed warrior tank". Now how exactly is the recently introduced 15% buff for random pickup groups helping that warrior in cloth armor to tank? It appears pretty obvious to me that even after the buff that "tank" will still be exactly as unable to run a heroic as before. On the other hand there is the average tank, who is wearing a not perfectly matched mix of blue gear from quests and normal dungeons; who has gems and enchantments, but is maybe missing a few here or there because he counts on replacing those pieces, and who didn't buy the most expensive version yet either; who has a reasonable understanding of what all of his buttons do, but might not be aware of the latest spell rotation or priority list from the theorycrafters at Elitist Jerks; in short: The average Joe. That is exactly the guy who will profit from a 15% buff, because it is just enough to change the game from "too hard for the average guy" to "doable and reasonably challenging for the average guy". It is exactly that guy that Blizzard is catering for, that Blizzard is designing their game for. Because that guy, and the average healer, and the average damage dealer, are making up the huge majority of Blizzard's playerbase.