I’ll just throw in my own pet peeves here.
The existence of .h files is still a big problem. I’m not aware of another language (besides c of course) that basically forces you to type the same letters twice in slightly different ways in order to expose a public api.
I also don’t understand why there’s still no way to print an enum value.
However there is some progress. I think std::span fixes the issue with the vector of const vs const vector. The Eigen library gives a (not perfect, but very convenient) matrix type. And I think I heard something about modules?