Key Vault for Connection string using secrets
The Key Vault implementation is widely accepted for security reasons and greatly simplifies the work of rotating / change passwords using secrets. When you have a big number of models this becomes a tedious job if you have hundred of models on top of a data warehouse.
The super awesomeness would be to be able to configure and entire connection from the secrets. When changing environments (Dev to QA or QA to Prod) would just take changing Key Vaults.