When I started using UE4 I used comment boxes extensively to visually group nodes and describe high level functionality. After a while however I realized that it took too much time to adjust all the comment boxes to keep up with the changes of my constantly evolving node trees. Eventually I ended up relying on compound nodes for structure: the mechanics are arranged into multiple levels of compound nodes where each level has the minimal amount of nodes. If a step needs more than 4 or 5 nodes than it gets collapsed into a compound node.
This kind of partitioning keeps the node hierarchy from becoming visually overwhelming: The developer can move from high level overview to deep into the belly of a particular implementation in distinct steps and see only a single level. This prevents getting distracted by lower level details and also makes zeroing in on a bug faster.
On the right is part of the BaseDrone class’s main Event Graph. While this is one of the most complex classes in Drone Alone the node tree remains reasonably simple. It can be read like text thanks to the descriptive function, variable and compound node names.