To me the key is representation - as long as that representation accurately reflects the wishes of it's constituents there is no practical basis in revolution. Why have a war that will destroy lives, material and wealth if you will ultimately lose on your issue anyway?
As broken as our current system may be, it does mostly reflect the wishes (or rather the apathy) of its constituents. One problem I see developing though is the immense amount of specialized knowledge necessary to run a country. How do you stay educated on that so you can be informed in your voting? Obviously you have to trust someone to analyze and summarize many issues for you. Who do you rely on to do this?