I seriously think someone should re-think C++ from scratch instead of driving away into another language.
A 'rethink from scratch' would just give you another language.
Anything which breaks backwards compatibility is a new language.
End of story.
And people have tried, D which was brought up earlier is this indeed incarnate, yet it has failed to catch on.
A 'rethink of C++' is no longer C++.
I think you should take my words with much more immagination. D is substantially different, C++ has different goals and try to keep them by forcing backward compability, what if C++ had to be designed nowdays from scratch? It will result in much more clean, simple and performant language with less maintenance burden both on client and compiler side.