This question sparked me to think: are we still using implementation ID for anything? Can we get rid of it? (The original purpose was for the OCC concept collaborative, but this has never been built out, and the purpose will now be fulfilled by OCL.)
As long as implementation ID is solely for OCC, we can get rid of it.
But, I thought the intent of implementation ID went beyond OCC – i.e., to avoid conflicts between concept sources for mappings. We should have a place for central registration of concept sources. While modules should be using a fully qualified module ID as a source for any vocabulary defined by the module, most implementations prefer to use something shorter than a fully qualified name for their organization’s mappings – e.g., a 3-5 letter abbreviation like “PIH”, “AMRS”, etc. We don’t want these being re-used by different organizations. So, the workflow may be completely independent of the old “implementation ID” thing done for OCC, but we should still have a mechanism for registering a concept source within the community.