I disagree with this. For applications where state drives output (IE, every single webapp) I find that change detection is a decent chunk of issue detection.

I disagree with this. For applications where state drives output (IE, every single webapp) I find that change detection is a decent chunk of issue detection. Change Detection + Business Flow Testing will probably deal with your stakeholder requirements far cheaper than almost every other method of 'ensuring quality'... even the classic lie of 'developers would never make that mistake'