If they do resurrect this,
it should specify _absolutely_
that only OP_RETURN transactions are acceptable for this feature.
Or, perhaps, only the OP_RETURN component is zero-fee.
You can also make more sofisticated schemes like if a coin has a certain coindays-ago, it should free to move.
This would be ideal. Regular users making occasional purchases should never have to think about fees, blockspace, mempool sizes, etc.
