[dwohnitmok]

Yes Clojure is all about first-order functions working on simple, concrete data structures.

Pervasive use of protocols and custom, user-defined higher-order functions I would argue is unidiomatic Clojure and creates long-term pain as you end up with opaque functions being passed around that can't be inspected at the REPL and a lot of tricky "fitting functions together" that is made difficult without a static type system. You sometimes need them, but you should reach for them very judiciously.

There's a reason Clojure emphasizes data over functions (and both over macros).