I think the steps to be taken are: 1. Prioritize. What are the most critical problems with choosenim? What features are lacking? 2. Announce. Make a blog post with the list of issues sorted by priority and invite the community to contribute. 3. (Optional) Reward. Offer a signed copy of Mastering Nim to the most prolific contributors.
P.S. I'm so jealous that you can freely quote Greek aphorisms untranslated :-)
