Make it possible in configuration file to change or add implementation of ReportOutputter, the same way that you can change (or add) dependency resolvers, latest strategies, expression matcher, conflict manager, namespaces and module descriptor parsers.
With custom report outputters you will be able to change the log format (e.g. make it cleaner, not to confuse users), use other logging systems (e.g. Apache commons logging, Log4j, etc.) and so on.
This match the current product architecture as much as I understand.