Clojure.
All kidding aside, one- or two-word comments are quite uninformative. Just because the original article with its "Scala is not a well-designed language" statement doesn't bother backing up bold claims with arguments, we should not fall into the same trap here on HN.
It's worth talking about Clojure as an alternative to Scala. They're both targetting the JVM, and they're both still on their way out of a niche. But just throwing out the name of an alternative programming language doesn't make a useful comment yet, nor does the "too succinct" reply.
Think about it for a second. Take a step back. Look again. It's poetry.
A very concise comment, on a very concise language is followed by a "too concise" comment. It's beauty.
For someone new to Clojure like me, the problem with Clojure is that it's so easy to overlook an existing function and spend a while implementing something which already exists, even in the core libraries.
I had a quick read to a Scala tutorial this weekend and what I remember the most is how ugly the syntax felt, even compared to other languages :-)
It's probably more accurate to think of each as alternatives to Java. Why the distinction? Frankly, the two seem almost diametrically opposed to each other in their approach to things. The properties of one that might attract a user seem almost totally absent in the other. At the highest level Clojure's approach seems to prioritize simplicity above all else (except perhaps pragmatism). Even a cursory glance at Scala's type system gives one the feeling that simplicity was not high on Martin's list of priorities. Scala's facilities for abstraction complect objects, types, and traits. Clojure prefers piecemeal abstraction (e.g. "polymorphism a la carte.") Even Clojure's reader macros, which are arguably one of the (relatively) more complex features of the language, are relatively simple compared to Scala's implicits. As Neal Ford said, Scala will probably end up winning the Java.next race because it "fetishizes complexity in exactly the way Java developers are used to." I don't think many users of either language view the other as a suitable "alternative."