yes  i agree about current API limitation however my point was most of key features / access can be done using API and have custom solution including historical logs , events etc.  Your use case is for Monitoring or specific to event audit which is nothing but a requirement to see who did what, when...

@Brad_morris  Cloud Manager API that allows you to retrieve information on pipeline executions, environments, branches, domains, IP whitelisting, execution and others can be used for tracking, what specific you want to capture here

suggestion, this could be done using Adobe IO Reading Cloud Manager API and Events - but will be  custom application deployed on cloud / server less @Brad_morris  

can you think about a custom rollout config based on the publish content tree workflow / where setting server instance to preview server

Did you check on the publish content tree workflow and have a custom workflow to publish content to the preview server