To get five star reviews on the WordPress.org plugin repository you either need to plan the plugin perfectly (hint: that's impossible) or have an effective feedback loop to continuously improve your product. After a product is out in the wild you have to see how people are using it; study what they do right, what they do wrong, and what they can't possibly do but try anyways. You can make tweaks, add new features, and improve documentation. This is what I've been doing for the past 11 months at WooThemes and I love it.
Support isn't a problem you can solve but it is fun to see how much of it you can eliminate with good documentation and self serve tools for your users. With 100,000+ customers at WooThemes every little tweak we can make to our products affects how many tickets we get. That's why when I heard about SIDEKICK I jumped right in.