What's the ideal pace for expansion releases?

It's hard to miss one of the major news announcements for the MMO world -- a release date for Cataclysm, the latest expansion for World of Warcraft. More than a few fans are intensely pleased that the date has been given, but it comes as the prior expansion is getting quite long in the tooth, and there's a general sense that this comes far later than it should. On the other hand, some people prefer the slower pace of releases, either because it takes them a while to move through all the content of a given expansion or because they just happen to like the setting.

For all that World of Warcraft is a trendsetter in the MMO world, its expansions come out almost glacially compared even to older games such as EverQuest. How quickly do you want expansions to come out for your game? Do you prefer large content updates marketed as expansions, or a boxed expansion every year? Every other year? Have you ever felt a game was launching them too quickly for the changes to be felt before the next one came along, or too slowly to keep player interest high?

From Massively.

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