the Try and Catch Errors nodes are very useful when working with nodes that can fail from time to time. The problem is, that the corresponding flow variables are only present in case an error occured.
I would really appreciate to have them each time the Catch Errors node is executed. You can assign some default values to them like "none" for the FailingNode variable because that makes controlling a workflow much easier.
please let me note, that this would be useful for the Catch Errors (Var Ports) node as well. I use this node to catch errors that occur using the XML Writer node.