Completely agree! I did most of this work and I wanted to add before-and-after benchmarking but I got busy. I have an in-progress (private for now) implementation of the Medium clone RealWorld [1] project. I want to make that public with some benchmarks, then write up a modern implementation in Rails so we can compare performance. It will also help people compare our code side-by-side, to translate concepts they know from Rails into our approach in Hanami.
[1]: https://github.com/realworld-apps/realworld