I felt like the blogs were almost a necessity for them last year, just to get the game some positive buzz. After M09 I think it's safe to say they most people were kinda meh on the game. But it's not like they just started blogging last year, they've been doing it off/on since M08. It's just that last year they went nuclear with it (blogging 6months+ before release).
It's hard to say how much the added interaction helped though. In some areas, it's scary to think where the game might've been at release if not for the community pointing out things like uniform errors and such. But I'm not so sure how much the community helps from a gameplay standpoint. One area the community hurt the game was the complaining about the robotic running animations. They were right, they were robotic. But Tiburon's efforts to change them mid-stream resulted in the running animations actually looking worse - a huge eyesore no matter how hard you try to ignore it. Another thing: from a community day standpoint. In years previous I always hated the usual suspects like Pastapadre and the crew going to CD, coming back and reporting how great the game was going to be. 07, 08,09 - always the same, never failed. And each time the game was disappointing.
This year's CD makeup was infinitely better. And post-CD most had their own positives about how the game was looking. Then once the game released... we had to hear "something changed" at some point between CD and release day that ruined the progress the game had made. I'm not sure what, but yet again the game at release was something of a disappointment. I'm just saying - I don't see the value in people being to be told what they want to hear, wanting to believe the fantasy than deal with the reality. Madden 10 was an improvement - that should be expected. It wasn't some MVP-like transformation. Hard to say if it's needed or even practical at this point. But I don't know how much the blogs benefit the community, other than them being the equivalent of having sweet nothings whispered in your ear.