The problem with std::string is that when I type a quoted string in my code, it isn't natively a std::string, it's natively a char* and gets converted to strings. C++'s biggest mistake was not standardizing early on an official object-oriented string datatype. It should have been in the first version of C++, it should have been treated like a primitive type (even if it isn't), and they should have said "thou shalt use this type for your strings". It makes me sick every time I see some goofy custom string class.
One problem with const-correctness is C++ uses "const&" to mean two different things: it could mean either a reference to a persistent object you're not allowed to change, or it could refer to a temporary object which you're prevented from changing because the changes will disappear. The problem is it conflated access control with lifetime. It would have been better if there were a "temp" keyword - although the last thing C++ needs is more combinatorics of type decorators.
On the subject of consts, though, C++ simply enforces const correctness more, but doesn't the same criticism of confusing const apply to pointers in C as well? You can just as easily declare a "const * const" in C as in C++. So I fail to see why Zed Shaw writing something in C gets him away from that "problem", unless he doesn't write const correct C.