I have two takes on the situation. First of all, not buying a game for being 7/10 seems ridiculous to me, but perhaps on a different level than others. Personally, I don't see anything wrong with being a 7/10. It means that it's above average to good, just not quite great. Or in the case with the Enchanted Arms review: 5/10 means it's average, and if you're a fan of the genre, that shouldn't have to be a particularly bad thing. It just means that it's not bringing anything new to the table.
As for me personally, I think it's just moving with the times. Being an old-school gamer, moving on is something I often do reluctantly, but in this case, there's no avoiding it. Back in the days of Nintendo Power, people liked video games. They were fans of video games. And there were two types of video game, and they were "good games" and "bad games." Games were based on their game mechanic being good (ie: fun) or not good (ie: not fun). Trace back far enough, and you'll find that there's at least one game from each genre that we know today that I really enjoyed, because it was a fresh new mechanic. FPS, RTS, RPG, hack and slash, dungeon crawls, adventure games, and so on and so forth. But now, those games that were innovative have splintered off and become their own sub-genres of video games, and things are getting convoluted. Now we have loyalties between one genre over another. Now we have to start thinking about games in terms of individual merits as well as where they stand within their fanbase. Now we have epic wars over whether or not Halo is a good game, because hardcore gamers say one thing and the mainstream millions say another.
What is good and bad anymore? Video gaming has become so widespread, and games have come so far since their roots that we constantly have to redefine what merits to base our reviews and criticisms on. A reviewer criticized Fire Pro Wrestling Returns on the PS2 because the graphics were sprite-based. Although I've been a fan of FPW for a long time and didn't need convincing to buy the game, I do have to say that one of my favourite aspects of the series is that it stuck to its sprite-based roots and chose not to move ahead to 3D polygons.
I wouldn't go so far as to say that reviews are useless, but I do think we should think about how we look at reviews. A few rules of thumb: 1) don't trust one opinion, look around and see what the general consensus is, and 2) more importantly, try to ignore the opinionated aspects and look to find the objective points. Don't read about whether or not the reviewer hated a certain feature, think about whether or not you would like that feature. Combine those two and reviews can be a fairly useful tool to helping you determine where your money should go.
Or, better yet, you could just rent the damn things.
But anyhow, I'm doped up on NyQuil right now, so I have no idea where to go from here or how to end it, so I'll just stop.