Support for proprietary error nesting in Ecto.Changeset?

Has it been considered so far to export cast_embed -like Ecto.Changeset nesting behavio(u)r for proprietary (business logic) error-handling purposes?
I am aware that it probably was not the original idea to host all sorts of error handling, but the thing is that there are different frameworks now that make use of the Ecto library and its Ecto.Changeset error convention, so my point here is that it would be great if we could reuse it for proprietary validations as well (i.e. without casting features - just for the sake of being capable to collect custom errors in nested Ecto.Changesets that can then be traversed with traverse_errors function).