I think an SQL + Ecto integration that allows control to which of multiple Repos the Query is send, would be valuable as it allows adopting the SQL + Ecto integration in brownfield projects.
Our use case is a data dashboard that pulls data from multiple, already existing, databases. In such a brownfield context, we find DBAs and peer developers that are not experienced in Elixir/Ecto already, and allowing them to contribute to a project with SQL queries, eliminating the need to translate them to Ecto.Query, would be a real boost and lower the barrier for Elixir adoption.
Your work is very interresting and relevant.