I wouldn't want to see this place become yet another review site, but I wouldn't object to a small review field for each game that shows up when people access our personal collections. Keep it really short (say, 200 words or something) so people don't get carried away and I think that'd be enough for everyone - short enough to ignore if you're not interested, but long enough that people who do want to add a little "Why I think this game is brilliant" paragraph can do so.