I’m far more likely to get 15 one-star reviews when something goes wrong than I am to get 15 five-star reviews when everything goes right. Perhaps it’s just frustration speaking here, but when Apple ties my hands behind my back and lets users punch me publicly in the face without allowing me to at least respond back, it’s hard to get excited about building an app.
The one-star review issue is unfortunately not confined to the App Store: the only people motivated to write reviews (wherever they may be) are those who are either not happy or those who are happier than they anticipated. The negative aspect there far outweighs the positive, sadly.
As to replying reviews on the App Store, this is my biggest gripe too. Outpost has had much the same issues, and currently has a 50% (2.5 stars) rating. A large part of this is due to a bug which has been discussed extensively on our Get Satisfaction support site, and which has a really simple fix (the app crashed trying to handle an ‘API not enabled’ message from Basecamp— solution is to enable the API, which you would need to do anyway). However, we got a deluge of 1-star reviews from people who didn’t look at the support site, just posted a bad review. We’ve even had people claim we offer no support, in publicly-accessible reviews.
These don’t seem bad enough for me to use the ‘report abuse’ option (demonstrating an inability to read does not constitute ‘abuse’ for me), and while this is the only option available I’m SOL. The ability—as an app’s developer only—to send messages to reviewers would be a great addition to the store, IMHO.