I have only a fleeting familiarity with Hanami and Trailblazer. It struck me that they are both achieving very similar ends. I preferred Hanami in that it retained very discoverable mechanics for people comfortable with recent low-level trends in webdev (e.g., Interactors are simply Service Objects) while Trailblazer seems to have its own heavily engineered high-level paradigms (e.g., Cells) that seemed more suited to the Rails way of thinking (geminize all the things!). Any paradigms/approaches that Trailblazer advocates that you prefer over Hanami?

Yes, they really have similar parts (mostly Operation and Action). But Hanami is a framework and Trbr is a architectural layer, that could be used inside any framework. In Trbr I really like the idea of Representable to convert objects. Trbr is more tailored for Raiks, to allow step by step improvement of existing Rails apps. Maybe it is not so important for Hanami, but with Sinatra it will still help a lot.