This style guide discourages multiple parameter lists, but it doesn't mention that they are useful for helping the compiler with type inference, as mentioned here: http://docs.scala-lang.org/style/declarations.html (granted, this is a bit of Scala ugliness, but it merits discussion).

I agree with several of their recommendations, but I strongly disagree with their general philosophy of "[feature] can confuse programmers less familiar with Scala". It's one thing for [feature] to be genuinely confusing, and an entirely different thing for it to be "confusing to novices / Java programmers". In the latter case, the right course of action is to educate them; otherwise we'd be stuck programming in Java++.