The supposed weakness of Scala as being "too complicated" or "too rich" can be countered by developing coding standards, creating more robust editors and tools,

The supposed weakness of Scala as being "too complicated" or "too rich" can be countered by developing coding standards, creating more robust editors and tools, and by better educating polyglots on how best to use Scala. This will never work. It never worked with C++. You need sharp C++ programmers to produce C++ code; you can't use mediocre programmers using a subset of the language. Even if you enforce simplicity internally, debugging and external library dependencies force all C++ programmers to cope with the full complexity of the language. Java is an excellent language for exploiting the abilities of average programmers. Average programmers can be self-sufficient in Java. Outstanding programmers, exploiting the full power of Java, produce code and APIs that average programmers can understand and use. Scala cannot fill that role.