As plugin's author in a contributive world, just a humble opinion:
Since 5 years, plugins repository seems to become more a shop or a factory (with customers) and not a exchange platform or a knowledge library (with people working together). I am happy to contribute to WP core debug or improvement via tracs. I will be happy if for free available plugins, users continue to comment and why not suggest patch... But, perhaps the world is changing...
Best regards,

Michel