First off you have to realise that America isn't really a Democracy, it is a Republic that puts more power in the hands of fewer lawmakers than many western societies, so I don't believe it is the best exampel of a functioning Western Democracy.
1) What would be your ideal state of politics?
While entirely realising the limitations of it - Direct Democracy would be the greatest form, however as Rousseau says (I have been quoting him far too much lately...):
Quote Originally Posted by The Social Contract
Were there a people of gods, their government would be democratic. So perfect a government is not for men.
2) Why do you think that people have not tried to change the current system? Why do you think such attempts have failed?
Because change is still possible from within the system and as such as long as people believe they have a chance to change the rulers and decision makers, they are not going to be willin to revolt - because afterall, what would replace it?