Actually, there are many objective metrics to measure the efficiency of the state existing nowadays for this very purpose. Economic growth as one of the most evident and encompassing example of such a metric. Also, how are you going to define freedom/liberty in more or less objective terms and would it be a moral issue then?
The problem is this: if you decide to use economic growth as a metric, then you are setting up economic growth as being valued more highly than other factors. Say some people would want equality over economic growth. Either way, this is a moral decision.
The basic principle is this: the ends (your metrics) don't justify the means. So some system might result in more economic growth, but that doesn't mean it's right to force it on people - maybe they value something else more highly than that economic growth. Or some system might result in better equality, but it would be wrong to force it on you or others who believe economic growth should be paramount (just an example). Or maybe reducing traffic deaths is the number one goal, or childhood obesity.
Your appeal only makes sense when it is directed to a human being for whom there exists a moral scale (i.e. by which he can tell that some decisions are more moral than others). But it would not be
my decision to set up economic growth before equality. State would be interested in equality as long as it has some influence on economic growth if it decides to prioritize that metric...
You just can't draw out a morally justified decision from an entity which doesn't have morality inherent to it