Every time I am looking at a possible purchase, I want to head to the forums to check out what others have said about it. However, there doesn't seem to be a direct link from each game page. If its there, can someone tell me where to look? If not, can the GoG team think about adding it? I would certainly consider it useful.

There isn't a direct link, but there is a workaround for this:
If you click on "comment" on one of the reviews, you will be taken to the review thread, which is in the game forum.