Programming in Scala(2.8), 2nd Ed.(preprint/draft book), Odersky, Spoon, Venners

The problem with that if they would follow your advice it would not be Scala anymore. There are dozens of programming languages which used more restraints in their design, but I've chosen Scala. The reason is that I don't want to use different languages for different tasks unnecessarily. Scala is almost a no-compromise solution: statically typed, fast, concise, supports functional style where I prefer that and supports imperative style where I prefer that. I've been programming in Java for almost 10 years, and it was a no-brainer for me to switch to scala. This is the most important production language for me right now. The only drawback is that it is not for beginners. It is for mature programmers. A beginner will be annoyed by the lot of information this book contains. But after lots of years of programming let's say in Java all the features in the language feels as a bless from god.

By the way the languae is not particularly complicated. Its language specification is someting like 200 pages while Java's language specification is something like 600 pages. The BNF syntax description of Scala is smaller than Java's. It contains fewer keywords. Scala is not more complicated than Java, rather it is deeper, and feel more complicated (espceially in the beginning.)

I think this lack of an arbitrary feature boundary makes it a useful research language. However, for the same reason, I imagine it's not so good in production — it's like Perl with "more than one way to do it," but now you need a PhD [1] to understand several of the myriad ways of doing things.

[1] You don't need a PhD, but I'm guessing only a very small proportion of working programmers know what, e.g. a higher-kinded type is.