I won’t repeat the surplus of adjectives used to describe DRAKON. Its long term use in the Russian space program is enough to recommend review of its visual techniques.
The DRAKO-Erlang project is an effort to combine DRAKON as a flow language/representation with Erlang.
A graphical notation for topic maps never caught on and with the rise of big data, visual representation of merging algorithms could be quite useful.
I am not suggesting DRAKON-Erlang as a solution to those issues but as a data point to take into account.