I also feel like CPAN needs a user interface improvement and I've also read the articles that Sam references. I would still like to see a ratings and comment system added to the site.
When I have to dig through a lot of similar options, I'm wondering "but which modules are other people using, and why?". A ratings and comment system would answer that question for me. I think this model has been established through sites like Amazon.com, Slashdot.org, and PerlMonks.org. The comments are important in addition to just having ratings, because the comments explain _why_ a module is rated highly. Maybe a module is rated highly, but for reasons I dislike. I could also take into account that a module that's rated highly from a pool of 4 people is not as meaningful as a module that's rated highly be 40 people.