I frequently copy integrated calendar entries as time. I have many repeating meetings, so it would be good if the copy function also remembered the project and tags of time entries with the same description.
Also, it would be good when integrating multiple calendars to be able to set default projects and tags for each calendar.
Edit: when copying calendar entries as time it might be useful to include a reference to the source?
Edit2: Also when integrating multiple calendars, colouring them in the external calendars list so you can tell which is which would be helpful