Matt and Dave,
Thanks again for your feedback.
I’ve re-written the paper based on it. Version 1.1 is available at GitHub - JohnLaw2/ln-opr: A fast, scalable protocol for resolving Lightning payments.
The new version focuses on the speed and scalability gains from the OPR protocol. The security of the OPR protocol is shown to be analagous to the security of the current Lightning protocol when making small payments. In both cases, parties follow the protocol in order to maintain their long-term reputation. In both cases, following the protocol prevents thefts.