Assuming you have lots of storage space, instead of drop you could just copy the table across to the archive. Similarly with dropped fields' previous versions,

Assuming you have lots of storage space, instead of drop you could just copy the table across to the archive. Similarly with dropped fields' previous versions, and created fields' current versions in the case of a rollback. But then you will also need to have the logic to create those fields for new rows. It's just easier to have forwards-only changes.