I'd start with the basics: A scanf() replacement would be nice, having a ostream/printf() alternative, but not something for input feels very unfinished.
Basic Unicode support is also still a mess.
Another thing I don't get: Why is uninitialized memory still the default? Why haven't they made the uninitialized state explicit in any of the numerous language updates?
Any C++ replacement language should support all the features of C++ to be suitable...