I think you first have to clearly define what aspects your trying to maximise. Maximising "happiness" doesn't seem to be viable, because you can just suggest that the human brain will be modified such that it will be happy whatever it does.

So, the first question in my mind, is to define what characteristics you want to maximise in society. Without such a set of characteristics it's hard to say "this social structure is better".

I also think it's unlikely that a clear consensus on this metric can be found. That is, if it is even meaningful to create one.