Thanks again for following up here. Any information is helpful.
I love that slices are just containers for your code. I think this is a huge differentiator from Rails and other frameworks, and is the leading selling point for Hanami.
I think conventions are important though. Users love their conventions–and their generators. They’re like a security blanket. 
They also provide the uniformity that allows developers to go from project to project (or job) and be confident that they will recognize the “Hanami Way.”
I say this just as food for thought. The current slices generator creates a full scaffold of actions, views, etc., in the new slice (and corresponding tests). This might just be for learning purposes, to orient new users, but it also conveys the impression of a convention.
Thanks again for your work and your feedback.