So what kind of consequences would making the Fed powerless have? From a regulatory standpoint (making environmental/business/civil liberty/civil right protections based on the state rather than the nation) some states are going to become quite terrible for the average person to live in. With these issues, here are some possibilities:
-Inequality doesn't increase too much at the national level, but states that already have heavily regressive tax systems and large socioeconomic/racial divisions (the Deep South, for example) will have inequality get even worse. The rich get richer because they have less taxes but the poor get little if any benefit. In addition, as corporations are taxed less businessmen end up with even more influence. Worst case, businesses completely control some states.
-Racial/discrimination issues increase in some states. Muslims and Mexicans are currently targets, but there are lots of different minority groups that could be targeted over the next few years. There will be protests against this, but the national government will be weakened enough that it can't do too much anyway.
-Some states become police states.
-On the other hand, states that are currently handling these problems will probably improve without the federal government holding them back. Ironically, these will be states such as California that like having a strong government, although at the state level the government will probably be strong.
-Environmental problems are going to be a big issue. If there's a large city that sits on a state boundary and one state is anti-environment[al regulation] while the other has strong environmental laws, what happens when pollution spills over? What happens if cars are legal in one state but too dirty for another? To meet regulations, will some businesses move factories over to states with little to no regulation?
-And of course a decade or so of progress in fighting global warming will be destroyed.
Some other interesting stuff could also happen:
-states become much more distinct and more like separate nations.
-large numbers of people migrate to states that are nicer to live in.
-quality of life begins diverging between states.
-and the risk of a general financial meltdown increases as banks are deregulated.
And moderately funny/ironic stuff that's much less likely:
-current heads of federal agencies succeed in destroying the government so well that they remove their own jobs.
-congress shuts down the federal government again but doesn't start it up again.
-people in the government start cutting each other's jobs