The main thing that seems to be missing, in my experience, is moderation.If someone can manage to make a decentralized forum-like moderation list, then we wouldn't have any use for centralized trackers anymore.I think it could probably be done by using public GPG keys as identities, then keeping changes in a torrent-distributed git repo where user-generated data is saved in GPG signed git commits.Then the only centralization left would be what branch/torrent people introduce to new users