Add both a verbose and simple form of statistics logging output. The verbose form is in the MDC as "spa.statistics" the simple form is in the MDC as "spa.statistics.simple". The choice can be made with logging configuration.
Enhance operation logging to provide a little control over viewing customer data. If the log level is set to trace then you will see customer data. If the log level is set to debug you can still see the SOQL but the soql will be sanitized to remove customer data.