Thank you @Dennis!
Although we want to encourage parallelized testing where possible, the core testing team recognizes the need for serialized testing and the need to annotate tests that cannot run in parallel with other tests.
Feedback in this thread has been light but positive, and the proposal is accepted. However, there remain some open questions about future enhancements to the proposed API, so the team requests that Dennis amend the Future Directions section of the document before we merge #535 into the repository.