Back in the day... you had a 'content release' or addition; it was just another patch... but thats not how it's done now.
Scott Jennings posted something over on brokentoys a while back about this same thing, during Land of the Dead development.
Take Darkfall... their first patch (1.1) was released as an 'expansion pack'; essentially re-releasing the game (it improved, according to Eurogamer...they gave it a 4/10 intead of a 1/10).
Warhammer Online: Age of Reckoning - put in some class balance (then promptly remove it), toss in some AoE Nerfs and Buffs (then... oh yeah, remove those too); add in some UI hooks (remove them due to exploitable code) and add it some content that you'd promised at release: BAM - Land of the Dead Expansion & Live Event.
Lord of the Rings - Toss some Class balance, new MvP characters, a new dungeon and new lewt into a mixing bowl and what do you get? BAM - new "Book" (aka Expansion) and Live event.
As Scott Jennings put it though "Some people are still just releasing patches.. and making them worthwhile"
Not arguing for or against WoW... but they're still "doing it right"