Hi Matthias,
I will put this on my to do list for Event Calendar Pro, but there are some complexities. In deleting events we must also delete the friendly urls that point to the events. Another consideration is if tickets were sold for the event do we really want to delete the event and orphan the ticket records? Or should we only delete events if there are no registrations or purchase history? It seems like one day we may want to be able to find out about the event related to sales and if we delete them it will not be possible to find out what event a particular ticket was for, it will have an event id that no longer matches any event. I will have to think through these issues.
Best,
Joe