Thank you for your review. I agree that there is plenty of room for improvement. Our team is working hard on improving DOCman further. Keep in mind however that lots of sites depend on DOCman. It's our responsibility to make sure these sites can keep running smoothly. That's why we steered clear of drastic code changes that could hurt the stability and security of DOCman for the 1.5 release.
We've already started work preparing for DOCman 1.6, so make sure to add your feature ideas to http://ideas.joomlatools.eu/pages/docman . But know that features and price are not the only things that make software great. You might want to read http://blog.joomlatools.eu/2010/01/why-docman.html
Joomlatools Managing Director