I think it would be great if there was an option for users to rate cards. The comment section is good for specific feedback, but the subjective feedback is lost. When asking about feedback I often hear "It's okay." which doesn’t help improve its usability. With an anonymous rating system more people would give feedback. With rating, authors can see in analytics which card is most liked and see how that card is written and designed, and try to use that as a guide for other cards.
I feel a 1-10 star system would be best, as a 1-5 star system often end up everybody giving 1 or 5 stars (example: Amazon's broken rating system, everything under 4,5 is seen as garbage)
The option to rate the card could be at the top, after "Comments", or at the bottom of the card. Somewhere fast and easy to use, not hidden behind a menu.