So this is a common issue on the clojure sub-reddit the two good responses i've seen to this is the library expound (https://github.com/bhb/expound) so you get more 'human' read-able errors and my personal favourite is Stuart Hallows blog post REPL DEBUGGING: NO STACKTRACE REQUIRED (http://blog.cognitect.com/blog/2017/6/5/repl-debugging-no-st...)

The same way you refactor any other mid size project? Refactoring 2nd ed by Martin Fowler mainly uses Javascript and Refactoring (Ruby edition) by Jay Fields are both dynamic. Tests cover you when refactoring not types.

Datomic: Event Sourcing without the hassle https://vvvvalvalval.github.io/posts/2018-11-12-datomic-even...

Stuart Halloway from the Clojure community has some great a talks using the REPL to debug.

Links:

Debugging with the Scientific Method - Stuart Halloway (https://www.youtube.com/watch?v=FihU5JxmnBg)

REPL DEBUGGING: NO STACKTRACE REQUIRED (http://blog.cognitect.com/blog/2017/6/5/repl-debugging-no-st...)

scope-capture (https://github.com/vvvvalvalval/scope-capture)

I been using a very similar pattern [Port and Adapters]http://blog.ploeh.dk/2016/03/18/functional-architecture-is-p... since moving to F#, paired with [Railway Oriented Programming]https://fsharpforfunandprofit.com/rop/ for the 'Adaptper' level and using DDD for modelling the 'Entities' & 'Use Case' layers' and it been working well for me so far.

Scott Wlaschin has recently released an [ebook]https://pragprog.com/book/swdddf/domain-modeling-made-functi... on the topic which goes into more detail.

These are all architecture ideas I've been interested in, I'll have to check out the book.

Overall architecture in development is still early on in maturity.