1. Disallow infix notation abuse through code review. Scalafmt can automate that for you. 2. I mentored a couple novice developers working on a Play codebase,

1. Disallow infix notation abuse through code review. Scalafmt can automate that for you. 2. I mentored a couple novice developers working on a Play codebase, the rough guideline was to use libraries that depend on Scalaz, Cats, Shapeless ... but never import any of them in our codebase. No HKT in our code either. (Nowadays I work with all that on a daily basis, you can keep things reasonable). 3. I think you're mixing up a few unrelated things. Scala's OO model is cleaner than Java's. Implicits abuse is avoidable with frameworks like Play.