Multi-paradigm incoherence? There is a huge difference between throwing multiple features/paradigms into one language (as C++ does) and integrating them so that they are orthogonal and don't get into your way (as Scala does). The integration part is the hardest thing and Scala designers did the great job there, assuming the constraints that were given.

Scala does have some rough edges but they are not the kind of C++ ones, and even the complexity of the most powerful features (implicits) is very controllable.

Seriously - which features would you like to remove from Scala? I'm really curious because I don't find any redundant ones. All are pretty complementary and very useful.

I'm not sure I'd remove any, but there is a huge incoherence in what is and is not "idiomatic" scala.

The most obvious example that comes to mind is whether you should use mix in traits or type classes for api design. Another one is the "magic-ness" of map/flatmap/filter for for comprehensions but no way to extend that for Functor/Monad/Monoid type classes.

Finally, the Scala community is a huge advocate of Algebraic Data Types yet don't support Disjoint types making any sufficiently complex system cumbersome to model as an ADT.

Thanks, that's really useful. It answers a lot of the irritating little questions that Scala's flexible syntax gives you, like whether or not to use dots for method invocation. I see that Twitter has a document on the best ways to write Scala, which looks interesting: http://twitter.github.io/effectivescala/