Honestly, I haven't read reviews of any kind in-depth in years. Why? Because they focused more on the premise of the game, any story it may have had, but given no real substance when it came to the mechanics. Screenshots and demo videos may abound, but that doesn't give the same feel for having a demo disc in your hand to get half an hour of even simplified gameplay to determine whether such a game is for you. What did happen to getting free demos with magazines, anyways?
In text, a game could sound like the most revolutionary thing in gaming to date with quick control response, high-res graphics, and any gimmicks the game hopes to use to get attention... Then you actually get the game and find out that the controls do respond quickly (but there are so many buttons you have to hit to find and start commands), the designs are very detailed (until you get very close, or perhaps there are little bugs in some designs), and that gimmick mentioned is either so useless that few people really remember it's there or it somehow does something that makes other parts of the game completely obsolete. There have been no reviews that I remember reading that pointed out the problems in a game because they were too busy raving about how "cutting edge" it was supposed to be, even if it really wasn't. At least that's my complaint with reviews...
And who's to say that review boards like IGN aren't being swayed in some way to find reviewers who would play a quick demo, watch a couple of videos, and jot down their first impression? With so many 8+ scores going around, it's easy for more jaded gamers, or those who just hate that genre/developer/specific title, to accuse the reviewer of being bribed in some way that other people just aren't seeing. Or it could just be that the reviewing process is based on an older system that makes any new games look spectacular by comparison.