I did not understand who uses only default containers without configuration or only the small possible container configurations? For such people a default UI is perfect.
E.g. Containers with Linked Data-Containers to store the Data outside of a container, or setting up a container with different parameters (company/server specific). For such things i need an extra system which can not be used with your or any other UI.
We build our own small template system to manage Domains, Subdomains and the setup of the software within a container. How could this be connected to your UI?
It would be great if your Template-System will integrate an API, so really configurable Templates will be possible. Allow external Scripts, or better access to an Rest-Api to get configurations. This will be a huge advantage over other standard UIs.