In terms of contents, I think the "next Wikipedia" might be an encyclopedia of projects. Each project would have its own standardized dedicated presentation page.
The purpose would be for project teams to be visible on a place of reference, so they could find supporters, participants, and resources. Reciprocally visitors could find interesting projects sorted by categories and places, for example near their home, and try to reach project teams. With such a worldwide project mapping, other applications could be done.
In fact I am very much attracted to this specific idea, to the point I try to create such a platform. But I still have a big remaining doubt: would this global platform add value for us, since there are already a lot of specialized websites presenting projects on the web (ex: video games projects on steampowered.com; ecological projects on solarimpulse.com/solutions-explorer; startup projects on... etc)?
I wrote a manifesto about this idea (everyone is welcome): https://projectofprojects.com/wp-content/uploads/2022/05/pro...