@Gavalakis, I found the problem, it is in class NodeCanvas.Editor.GraphAssetPostProcessor.
This line: AssetTracker.BeginTrackingAssetsOfType(typeof(Graph)); after run Editor trigerred calls serialization/deserialisation for each graph in every Reload Domain!
When I commented it, time to Reload Domain decrease from 14 second to 2.5 seconds for my graphs set.
vandelpal
