- Localization: Are you ever planning on selling this to someone in another country?
- Viewability: Do you want anyone over 40 to use this? (hint, software users are over 40)
- Extensibility: What makes you so sure this API will always be internal?
- Documentation: People do not buy software solely based on powerpoints. You need public docs. The docs have to be more useful than stack overflow.
- Affordance: UI is not a word. The microtext matters.
- Acceptance: Have you shown this to any actual humans who are like the users?
- Accessibility: We all use computers different ways. Does your software allow that?
According to Heidi, having these fights early prevents you from doing the software equivalent of poking chocolate chips into already-baked cookies.