I suggested this once a while ago as well (as I'm sure other people have). The more I think about it, the more it doesn't seem necessary. We already talk about the news stories on games on the forums and it would be a shame to see them become less active because people have already said their piece on the matter on a comment box. Also, now that I am a reviewer I would never want a comment section on reviews! XD
Who is the most vocal when it comes to game reviews? The people who disagree with you. People who agree with you never say so, they just nod their head and get on with their business. If someone disagrees with you, you will know about it, then in a years time when people look back on that review they are just gonna see a big list of complaints and then it will make it seem like you didn't have a valid point.
That's just the way I see it, anyway. The guys in charge may have a totally different reason.