Adaptability: How fast can the system be altered and customized to their needs? The NHS has strict rules governing patient data, even low-level data like name and phone numbers. He doesn't yet know what changes to privacy legislation will be required post-Brexit. Will the software be up to the job?
APIs: Ethan oversees APIs for many different systems and knows from experience how fast these can change. Can the new software integrate with all of the necessary APIs, at what costs, and how well are these documented?
Ethan represents a segment of users who understand the technology and want to know how it all works, how the software will be developed over time, what each solution can and can't do. These users tend to ask pointed and harsh questions online and do not hold back with critique.