I'd like to see optimizations targeting ctypes, or a successor to ctypes. I wish I could write elegant, performant C wrappers in pure Python. Right now the best choices are Cython, which is a hassle (separate, slow compilation, various warts), and ctypes, which is slow (and has some design problems of its own). Julia's ccall alone is a major selling point over Python right now.
I'm excited about WASM here. https://github.com/wasmerio/wasmer-python lets you call WASM binaries from Python, which means if you can compile a C library to WASM you can then call it from Python... without having to worry about introducing crashing bugs and security vulnerabilities thanks to the WASM sandbox.