The Device Scope and Usage is very specific about the fact a Device may have a UDI. I clearly understand the benefits of a UDI especially for implanted devices. And the Cardinality for Device UDI is 0..1. However, the Scope and Usage second paragraph could be more explicit about how to handle a device that does not have a UDI, specifically reusable and disposable non-implantable devices.
Boundaries and Relationships - Should have some clarification about how documentation about use of a device (especially non-implantable devices). The DeviceManifest resource seems to be the R5 version of DeviceUseStatement is DeviceManifest which seems to be a document for text description of what happened with respect to a device. However, it is not clear if information about a placement/removal of implantable device or use of a device should be handled as a Procedure or, for information about patient usage as an Observation (e.g., use of a wheelchair or other assistive device, or use of a monitoring device such as a glucometer, or use of a treatment device such as a CPAP machine). Clarity is very important for consistency.