The trickiest bit of Wasabi is the type inference, which I admit is not "production-ready" (or "good code") because we basically invented it from scratch. If I were to do it now, I would know just enough to realize that I need to read about Hindley-Milner rather than reinvent the wheel.

Producing human-readable output is an exercise in tedium and bookkeeping, not any particular amount of skill or brilliance.