Morning @quarfie,
Personally I like this idea a lot. Two remarks:
Is there any reason why you want to apply it only to outputs. Because if you have a N-to-1 node relation (with a large N) then it would be usefull to have it also on inputs imho..
Yes if you would have such a property dialog, you would be able to add - in the future - other features. For example a checkbox "Add routing info to msg". To support something like discussed here? Just to mention why I like your proposal...