Some things I feel would take the forum to the next level are
- A ticket system for resources: Users can directly get support through your website from resource authors, increasing activity and helping staff to resolve user reports of broken addons or inactive authors etc.
- Jobs section: Users can post a job with a title, description, needed skills and budget. Others can apply and can be accepted by the author to complete the job, a new type of reputation can be introduced this way.
- Host ranking: Introduce a host review system where hosts can invite clients to upvote with a few words or something similar with a leaderboard for specific types of hosts, game, web etc. Introduces more reasons to visit the site, competition and more users