I have a related concern with the idea that the Bitcoin Core source code is the Bitcoin protocol specification.
Eventually, the C++ language will go the way of COBOL. Very few people will be able to interpret and maintain the specification in the not-too-distant future.
COBOL was never designed as a general purpose language. Part of the problem with C/C++ is that we are absolutely, irrevocably stuck with it because it is so integral in so many things. It means that newer and potentially better-designed languages have slim chances of succeeding because of C++'s dominance. It isn't going anywhere anytime soon.
With that said, it might be beneficial to move the core to some high level language/script that is then interpreted by a C++ or any other compiler.
additionally, still there are many improvements for C++, some people thinks C/C++ still has 1999 standards. People should look at C++11, C++14 and C++17 standards to understand how powerful language C++ is.