I agree, it's multidimensional. If "general" truly meant general purpose, the measure might be how well the system arranges every possible (sequence of) combin

I agree, it's multidimensional. If "general" truly meant general purpose, the measure might be how well the system arranges every possible (sequence of) combination(s) of matter and energy in space and time, while optimizing along any combination of these. But that in itself is not a single objective, but a set of objectives, and not really a utility function.