There is nothing stopping you from forking the project and adding all the enterprise functionality you want.
"The primary orchestrator going forward is Kubernetes. Mirantis is committed to providing an excellent experience to all Docker Enterprise platform customers and currently expects to support Swarm for at least two years, depending on customer input into the roadmap. Mirantis is also evaluating options for making the transition to Kubernetes easier for Swarm users."
https://www.mirantis.com/blog/mirantis-acquires-docker-enter...
Also, I haven’t needed to integrate something like Vault because the Swarm secrets feature covers my use case perfectly.
I currently have my secrets stored in an encrypted text file in case I need to bring them back up.