In the fantasy post-American commonwealth, or republic, or whatever, one of the socio-political realities that should be incorporated into the structure of government is the difference between cities and everywhere else.
A major reason why Official Sacred Victim Groups have so much power is that they are concentrated in cities. And cities dominate culture.
So whatever kind of federalism the new country has, it ought to leave behind the notion that a state is one of its fundamental building blocks unless it is willing to see cities of a certain size as city-states.
And to build into its constitution a way for non-urban populations to have some power balance against them.
The current Senate, for example, is clearly meant to balance the power between large and small states (population-wise). On paper, this means that Wyoming has as much power as California.
But in reality, major cities in the US are the real centers of power (and identity), not states.
Los Angeles, New York, Chicago, etc. really should be city-states. So that non-urban populations have some defense against them.
That's just government, of course. When it comes to culture, money, etc. I don't know of a governmental structure that could (or should?) try to deal with that.