I disagree. I think that a narrator can have a very positive or negative impact on a game. Much like a really good announcer can make a mediocre event seem like a classic or can drag an exciting game down, a narrator can do the same to a game. If a narrator rarely updates on time, or goes 4 or 5 days on average without updating, it causes the game interest to plummet. Players stop checking the thread as often, the conversations stop, and momentum grinds to a halt. Also, lackluster updates on the narrator's part can dull the edges of an exciting game. There is a huge difference between a monotone "He has successfully hit a baseball over the back wall and the Cardinals have achieved a victory" and hollering "Go crazy, folks! Go crazy! Its a home run! Cardinals win! Just like there is a difference between "Atreyu was killed, he was a villager" and a really nice long gruesome, awesome, or hilarious night kill scene. Anyone else remember in AC:II whenever Banjo made that post after Shadow was killed and the whole thread was thinking "HOLY CRAP ON A TUBA! WE ARE DOOMED!" That really added a level of emotion to the game.
In closing, a narrator can do a large part for a game based on their efforts in making sure they have accurate updates and also exciting posts. The players feel and react to the energy that the narrators put into the game. Please don't sell it short.