> Malloy closes with the exact same old state

Malloy can't close with the same state transaction twice - you can't double spend. There is a clear sequence of transactions. Each presigned uncooperative channel-close transaction is invalidated by making it possible to spend all outputs of that transaction by the counterparty. There is no back and forth possibility in curent lightning unless I have horribly misunderstood something.

I also share d5000's concerns about incentives. Currently, the cost a cheater incurs are:

A. Sending the out-of-date uncooperative channel-close transaction spends fees (presumably half of which came from the cheater, and the other half from their counterparty)

B. When the counterparty claws back the outputs, the cheater loses all their funds. This also covers the cost incurred by the counterparty in step A as a result of that transaction spending some of the counterparty's funds as fee.

With Eltoo, it looks more like:

A. Same as before.

B. Sending a newer state transaction again spends fees from both parties.

Is this corect? If so, it means that the cheater does incur a cost, but its the same cost as the cheater causes the victim to incur. So in this case, a griefer who is willing to lose as much as their victim could grief at 1 to 1 cost. This seems less than ideal.