I don’t disagree that this is would be a nice feature, which is why I’m asking for more details and collecting ideas for how it might look.
It’s not going to be a priority for us to implement as an official feature until more of our own customers ask for it. Having extra data in the database is not necessarily a problem, especially on our hosting where storage rarely is an issue.
A good first step would be to look at Bianca’s code in Introducing permanently delete post functionality and see if a bulk delete rake task could be created that is easy and safe to run. We have many rake tasks that are perfectly safe, and also many features that make it into the UI eventually that start out as rake tasks.