Building a Successful "Open" Game World

M3rk sends an excerpt from an opinion piece on Gametopius discussing what it takes for an open game world to be successful. Interesting stories and characters are important, but they must be balanced by varied and entertaining gameplay. The lack of either will be a limiting factor in how many people return to play once the primary plot is completed. Quoting:
"A game like GTA IV takes itself and its fiction very seriously. It spends a lot of time, effort, and gameplay resources convincing you that the world you are traveling through is the same world that the story and cutscenes take place in. It may not be a game that allows you to own or control property to the degree seen in Burnout Paradise or Saints Row II, but it wants its world to be cohesive, not divided. ... While GTA IV's game systems almost serve its plot, Saints Row II and Burnout Paradise live for their game mechanics. Sure, these worlds are fun to look at and explore, but any exploration and discovery that the player enjoys merely drives them to these games' raison d'être: fun systems to play with."

http://games.slashdot.org/games/09/03/04/0141246.shtml