I'm disappointed that we can't have general support for future versions of msvc. We don't seem to have this problem with pre-release versions of GCC/Clang.
As far as B2 is concerned it would be as easy as using the compiler reported version for the B2 toolset version. But that would probably mean breaking everyones build files. Which I'm fine with, but I can see others might not be. In all of this it doesn't help that msvc versions are so horribly muddled.