Introducing /run

IMO it's not correct to say that the shell scripts have been replaced with C. The logic of the init system has certainly been rewritten in C. Some daemons have been modified to be able to be run without needing to do any shell parsing (and I don't understand why it would be a bad thing). But what dictates the behaviour of the init process is not C code, but configuration files. So, most of the real meat of the init system has not been rewritten in C code, but "systemd configuration code". Which are easily hackable...