We have the same wish, i.e. to be able to delete past webinars.
Right now, e.g. webinar insights is of no real use to us, as our test webinars and webinars that I create for dry-runs show up in between the "real" webinars.
If you think this is an 'idea' then somebody should tell LMI that this feature will be mandatory in the new European dataprotection regulations in 2018. Nobody in Europe would be allowed to use the system if it is not possible to delete personal data that are collected with webinars. So at least the participants of the webinars must be deletable if not the whole webinar.
In Germany many companies use the system despite it is already forbidden to use systems where personal data cannot be deleted after the intended use. The pernalties for this are low until now but with the new european regulation will have penalties up to 10.000.000 Euros.
So i think this feature will be more than an 'idea'.
While organizers do not have the ability to delete webinars from their history, we can delete your entire webinar account and history as per GDPR compliance if you close it. Please contact Support and make that request.
(updated 9/27/18 for accuracy)