My memories of this system consisted of a great deal of moomoose's topics getting trolled by others. Sure, let's give it back to the CIA section 
I really didn't see much use for it personally, but if other people found it important then I don't really have any objections aside from the possibility of trolling.
Decks and CI&A are the two areas its really most useful.
It gives the community a means to provide a little extra feedback on overall impressions.
For card creators, it gives authors a way to gauge what the community thinks of the card overall so they can have a rough impression of how it will far before submitting it.
For decks section, it gives a simple way to rate decks so users can sift through the volumes upon volumes of various decks out there.
Adding in a minimum post requirement, as others suggested, would probably be a good idea to help lower trolling abuse.
What would be really cool is if it could be extended to allow multiple categories.
E.g. have something like
art, mechanics, theme, originality - for card section
ease of use, originality, functionality, etc. - for deck section
The rating could be visible as an average of the categories and would show the breakdown on mouse over, pull-down, viewing, or whatever would work.
This would be optimal since it would allow for much more useful feedback from the system... though it would probably take a lot more work, and people would need to agree on what the category set would be in each case.
