If the content isn't enjoyable without the carrot, then the content is not for you...

[kranur]

It's not as simple as that in an mmo where the big point is improving your character.

Remove levels and all loot. Basically how you start is how you'll always be and see how many people are willing to do the quests, dungeons and raids.

[sunnycutie]

Content is often only really exciting the first time you do it. Just like when you play a new game. You play it once, in most cases and then move on. You might return, but you need some time in between for you to regain some interest in a second playthrough.

I actually prefer a dungeon design where you are only supposed to do the dungeon once for the quests, and then move on. Once content has been played through, Blizzard needs to design more content. But they broke with that in TBC when they introduced heroic dungeons. They want people to run things over and over because otherwise subscriber numbers will drop. Blizzard are the ones putting the carrot into the game, because they know their content has limited replayability without it, and they can't design content fast enough to keep players subscribed.