Hello Dave and sorry for the late reply!
Welcome to the forums 🙂
Please let me address your requests:
1) This is a nice suggestion and something that has previously been requested. Another user even made a extension such as this (posted on the NodeCanvas forums), but unfortunately no longer works in the current version. I plan to add this feature in the future and was hoping it would be there by now, but I really have to refactor some other things first, thus to support this feature more “elegantly”.
2) This is something I want to “fix” apparently as well, but (apart from the accidentally editing asset possibility) it is actually quite hard to correctly implement. Basically the tricky part is replacing the asset currently in the editor with the instantiated graph of that asset “when” it is actually instantiated, but I understand this can be frustrating in certain situations, thus I will take another look at how to nicely implement this ability first thing right after the next version is send to the asset store!