OMI stops on errors and lacks meaningful output

We use the OMI tool in eGon-data to check the metadata. It is quite helpful but lacks some speaking output:

• Optional keys do not seem to be checked, a warning would be helpful #35
• If there's an error (more precise: some format problem, e.g. mandatory key is missing) while processing, OMI immediately stops e.g. stating omi.dialects.base.parser.ParserException: metadata string does not contain an id. In my opinion it'd be better to parse the entire metadata and give a list of errors/warnings, otherwise one might end up in a trial-and-error odyssey.
• Lacking details where error is located: e.g. if there's a malformed string OMI prints dateutil.parser._parser.ParserError: String does not contain a date:. Pardon, which field?