That is very simple to answer, even though philosophers through the ages didn't like the answer, and tried to obfuscate the question.

An economic system is good, if it is good for me (if it brings me happiness, and if it avoids my suffering).
An economic system is bad, if it is bad for me.

Good (ethical good) is what is good for me.  Bad (ethical bad) is what is bad for me.  There's nothing else. 

Of course YOUR good and MY good are not in agreement ; so we have to play a power game.  We might find an agreement where I understand that if I want too much of my good, inflicting too much bad on you, will motivate you to do bad things to me ; and vice versa.  Your ability to do bad things to me, my ability to do bad things to you, is the collateral we put up to find a mutually beneficial agreement.

I think it is the fundamental property of conscious beings, because conscious beings experience joy (good) and suffering (bad), so they optimize their actions for maximal good and minimal bad.

Society (as a whole) is not a conscious being.  So there's no such thing as "good for society" and if ever there were, society will have to decide for itself, against me (and against you).