Any particular reason why you'd like need to save a post as a draft and not post it for months?

I can guarantee you that not many people use the drafts feature or even care about it, so this whole feature exploration thing would only happen for a handful of people , if it were to ever happen.

If the main reason for this is for getting access to your deleted posts, then the more better solution would be to get pms for all of the deleted messages instead of a select few.