He should be blamed. If you look at the Blizzard financial statements, you can see how much budget is being cut from WoW year after year to show better and better profits. This is undoubtedly the primary reason the game has less and less content each expansion.
However, most people don't understand how the corporate world works, so they aren't going to get this important fact. Instead, they'll just listen to the "Rah! Rah!" statements that he makes.
"The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is." - Winston Churchill