As with any online community there will always be trolls and people who think they can say whatever they want behind the veil of anonymity online.
It gets a little complicated when dealing with ratings, because someone could game the system if the rating system isn't developed properly. Plus you then have to weigh in the knowledge of the voter, someone new to the game could rate a 10/10 when they know very little about all the possible cards or about the deck itself.
I am thinking more of a digg style rating system or Facebook "like" style to help combat trolls. the other way to help combat trolls is to also "thumb down" comments, again this increases complexity of a rating/comment portion but could also entice more community oriented feedback.
A simple "like" button would at least give the community a metric of what is popular and what is not. I know there is FB integration already, but I don't ever plan to muddy my FB profile with stuff outside FB.