Thanks for your input guys and that great discussion how to make GPLDL better. A lot of the things that you mentioned here are right and do apply but let me answer some of the points in detail.
Security is always first: Saying that, we will not accept anything that is not 100% bullet proof from anyone who we cannot 100% trust. We will not use any nulled stuff from some dark corners on the web just to extend the catalog. We like what we have right now, everything is as secure as it can get and we are not in a rush to change things. We are on the other hand very much interested in ways how we can open up to let users participate actively and share their 100% GPL Themes and Plugins. Unfortunately we could not find a way to allow this without taking on a security risk, which is – as said out of question. Brian’s idea to allow trusted moderators may be something worth considering under very strict selection criteria.
One more thing: Curating the latest updates is indeed a time consuming process especially since we have to manage a lot of accounts with various developers (lots of sources to manage). Fortunately our time does not need to be paid for, since the whole site is strictly built for philanthropic reasons and we enjoy providing WordPress items especially to those who are curious to try something new and those who cannot afford to pay for a license anyway. All the donations we receive go directly into maintaining the site and growing the catalog.