I don't think there are very many people not claiming that WoW subs are in decline, even those content with the game. It's been almost 9 years. These things will happen. It's more a testament to their willingness to tweak the gameplay formula repeatedly to retain them as long as they have.
Also: As far as revenue losses goes -- last I heard, Asian accounts only made up 10% of Blizzards total profits. So assuming the majority of their losses over the last 2 years have been from WoW China etc. it's not nearly as bad yet as some are imagining. The Asian sub numbers have always been rather fickle, so my guess is there is just some new MMOs on the block in China that are drawing away that crowd with games more appealing to Chinese gamers.