> It would remove most criticism from the language while substantially improving the correctness of programs.
How the mighty have fallen. A language with more than decade over Go and billions in investment by top tech companies and literal monopoly over enterprise usage need to even think of user share of a marginal language.
Except you are off base giving too much value to Go.
What is driving value types in Java is HPC and HPT companies in places like stock exchanges and biology research that want to move away from C++ into JVM land, but still need to keep some C++ around due to value types or make use of com.sun.unsafe tricks.
Nothing to do with Go.
Also Go's advantage in using value types will vanish when Java finally gets to have them, although we still need to wait for Java 10 for them, while Go is available now. So Go does have a few more years to gain developer mindshare.
Still Java isn't the only game in town, and there are other alternatives with GC, value types, more expressive type systems and battle tested concurrency frameworks.