It appears Google does listen, it just takes them a few months to respond. Almost 9 months after it introduced feed sharing features to Google Reader, the team have announced new features to allow you to control said features.
First, you can now select which friends see your shared items:
Another needed feature, when someone shares their items with you, you’ll get an alert and the option to subscribe to their shared items. You’ll also be able to decide whether you share your items with that person in return.
Next time you log into Google Reader, take a look at the new features. Then head back here and let me know what you think, or what’s still needed.