I think that the current system could be vastly improved with a few simple, though politically difficult, steps:
1. Resurrecting the FCC "fairness doctrine" and the post-World-War-II media decentralization requirements. This would break down the system of political control of public information that has emerged in the past two decades.
2. Making voting a duty of citizenship. This would require that political candidates respond to all citizens, rather than pick the groups they think they can most easily gain the support of. As it is now, we have the most political, the most fanatical, and the most scared determining election results.
3. Adopt improved voting systems and systems of representation. No voting system is perfect, but our current system, plurality voting, is enormously vulnerable to spoilers—we are getting a horrific taste of this with Clinton and Obama—and it can be easily gamed as well. The instant runoff system has gained some traction, politically; there are other systems that might be tried as well. At times, also, US legislatures have used proportional systems. I think we need to experiment with these and begin adopting improvements; what we have now is failing. William Poundstone has written an excellent introduction to this subject; I recommend it to anyone seriously interested in the forms of democracy.