To count recipient profiles and gather details like email, first name, last name, and the total number of subscriptions, the developer should use a workflow activity in Adobe Campaign Classic. Workflow activities, particularly query and aggregates, allow the developer to filter profiles and compute counts based on specified criteria.
Using a workflow is efficient for this task as it provides a visual interface and built-in capabilities for data selection, filtering, and aggregation. This method avoids the need for complex SQL or custom data schema methods, simplifying the process and leveraging Campaign's native workflow tools for data processing.