”That means a recently acknowledged write may not show up until the next refresh.”

Which is why you supply the parameter

  refresh: ”wait_for”

in your writes. This forces a refresh and waits for it to happen before completing the request.

”schema migrations require moving the entire system of record into a new structure, under load, with no safety net”

Use index aliases. Create new index using the new mapping, make a reindex request from old index to new one. When it finishes, change the alias to point to the new index.

The other criticisms are more valid, but not entirely: for example, no database ”just works” without carefully tuning the memory-related configuration for your workload, schema and data.