The thing this reasoning overlooks is that apps are complex tools that people use in very different ways, and it doesn't make sense to force people to reinvent

The thing this reasoning overlooks is that apps are complex tools that people use in very different ways, and it doesn't make sense to force people to reinvent the wheel everytime they want a feature that your use case studies didn't predict. How I think it should always work is: (1) back-end layer > (2) very customizable GUI layer > (3) highly tuned sensible defaults and presets. The great thing about this approach is that if you include analytics, the users to the UI testing for you: if you introduce an optional UI feature and see that a large portion of users do activate it, then you know you should make it the default or include it in some preset.