We do this currently with Apple Script for some time now. But it would be nice if we had a script step to issue a notification when some action is done.
Another nice UI thing to have would be a flash dialog where you get a confirmation in some way that some action completed. Just like when you increase or decrease the volume level on your mac you get this (see attached image) for a second and then it fades away. Would be great to group all these enhancements under UX improvements ...
Ability to include an image and make the background transparent. Along with a duration to fade in, stay visible and fade out time.
This could be really useful for actions where you need to provide some confirmation that the action was done.