It would be great to be able to validate data given the data sample + the shape file.
It could be also useful to validate the date given the data + the ontology (URI or code) in this other case the shapes should be generrated too by the service (and probably output).
The validation API should notify if some types in the provided data are not "covered" by the provided shape in the resultant report. If data has types nos covered by the shape, the report is always positive. In this way a user may know at least that the data is validated correctly because the shape does not cover the types in data.