I would argue that the underlying forum software Discourse is superior to phpBB, however, the customizations to support Go diagrams and an embedded SGF player are nice features of L19.
With a bit of work, it could be possible to add Go diagram support and an embedded SGF player to the OGF. Actually, in the past, this Discourse forum did have EidoGo embedded, however, at some point some updates to the forum software broke EidoGo functionality and there was no effort put towards maintaining it. There are also some security issues with EidoGo, which may be mitigated by a third-party patch (that I wrote and OGS deployed), but overall that codebase is quite deprecated. I would instead recommend deploying BesoGo as the embedded SGF viewer (full disclosure: I wrote BesoGo).