Ethic from Kill Ten Rats said this on Twitter today: "Reading MMO forums sucks the life AND magic out of the games." I completely agree.
It's not just the rampant pessimism and bickering on forums. It's that approaching a game from a designer's view steals some of the fun. It's easier to accept or ignore flaws when you're not thinking about how the game could have been better, how it might be improved. It's more fun when you accept a game as a finished product.
That's a major issue with MMOs, but it applies to all games. These days, all games have forums and fansites. Developers of all games request feedback from would-be players. Feedback is great. It's important. But it's also a double-edged sword.
The more you invite players to be armchair designers, the more difficult it will be for those players to enjoy your game.
That said, feedback isn't the only benefit. If a fan community is well attended to and not heavily moderated, with developers interacting with fans directly, that fosters personal connections. And personal relationships can be a factor in whether or not someone decides to give a game a chance. Still, I think developers should be careful in encouraging players to take on the role of design consultant.
Let players be players.