Yes, not all complexities are created equal. Haskell, and to a bit of a lesser extent Scala, have a lot of their complexity arise from combinatorial explosion

Yes, not all complexities are created equal. Haskell, and to a bit of a lesser extent Scala, have a lot of their complexity arise from combinatorial explosion of interactions of simple features. Also, relentless abstraction (particularly in Haskell). Yes, you can think of lots of things as arrows. But does it necessarily make it easier to write a particular problem to do so, or does the cognitive load required to maintain the abstraction <-> problem mapping outweigh the benefit of casting it as the abstraction?