The NSW Fair Trading Complaints Register is limited in the data it shows. It indicates the number of complaints made about a business, the location of the business, and the product type. It does not provide any information about the nature of the complaint.
There is more than enough complaints data available online to be aggregated by regulators to show trends in consumer complaints. This would involve drawing from different data sources such as social media channels, reviews sites, news outlets - to provide consumers a more fuller and useful picture of dodgy practices or products.