profunctors VS kernmantle

We’ll also use contravariant-extras, vector, profunctors, and tuple packages to make a few things tidier (this isn’t required; it’s all copy-paste anyway).

Edward Kmett already added a superclass to Profunctor, but releasing this got stalled

One of the main problems with the Arrow hierarchy is that it’s not particularly well-factored. The main Arrow class has five methods, which is both intimidating to newcomers and indicative that there’s some decomplection that can be done. I think the best alternative is to use the profunctors package; it deals much more fluently with things that can take values and then return them (functions, Kleisli arrows, etc). For example, the Arrow class is broken down across Profunctor and Strong. I had a term rewriting engine that used arrows, and I was never really happy with it until I moved it to profunctors.

Indeed, that is a somewhat contrived example that is meant to illustrate that ScopedTypeVariables aren't just limited to standalone type signature declarations—they can also be used in arbitrary subexpressions as well. Whether you prefer to use type signature declarations or expression type signatures largely depends on your personal tastes, but both styles are used in the "real world". For instance, here is one example of a use of expression type signatures + ScopedTypeVariables in the profunctors library.¹

So I'm wondering if Arrows are still the state of the art or if there's something else we should be looking into. I know there's kernmantle, which seems really nice, but it can only handle linear pipelines so it seems much less flexible, almost like applicative with extra steps (no disrespect to the maintainers intended).