When users inadvertently delete issue(s), getting them back is a royal PITA. Ie database restore, import into new instance etc, copy across somehow.

Would be nice if deleted issues could be moved to a per-project recycle bin, as per confluence. That way if you needed to get them out they'd still have the same ID.

BTW - I am aware of workarounds involving a Delete workflow action and issue security schemes, but I don't think that cuts it.