Well it truly is a complicated subject.
Is Democracy the best way to go for humanity? That's debatable. Are our current political and economic models the ideal for humanity. I think our current problems indicate otherwise.
Personally, I feel a Democratic system and a Capitalist economy do not work well together. Simply because of how they function. Capitalism is built around a Darwinist premise of those with the most cunning and skill (and connections) are the ones that get ahead in life. It is an egocentric Dog-Eat-Dog system that is focused on the rapid consumption of resources, with little long-term future vision, and little regard for the community. Then, if we look at Democracy, the entire foundation of the political model is that of "Power to the People." Where even the poorest and least educated have equal representation. So clearly when one blends this concept with the egotistical nature of Capitalism, you create a strange paradox. Ideally, the best way to have Democracy TRULY function, is by combining it with a community driven political model. One which caters to a slow and stable growth, while accounting for the well-being of all individuals. Indeed, I am referring to Marxist Communism. Lets not forget that Capitalism itself is also a rather new economic model that was born around the same time as Communism (the British Industrial Revolution of the 1800's). So Capitalism is no way a staple of Human society (modern society yes, but there have been other strong and stable civilizations in history that were devoid of such economic model), and in order for humanity to further advance, a more stable economic model must be implemented.
However, this brings about other interesting questions. As stated in the OP, is Democracy REALLY the ideal. As I said, that's very debatable. Is it really alright to allow everyone a legal right to vote? I'm personally inclined to say "No." In a society where most people are only concerned with themselves, and not the world around them it would be ideal to require people to acquire a "Voting Licence," similar to a Drivers Licence, if you pass a culture, history, and general knowledge exam, you are endowed with the right to vote. However, as already stated in this thread, ignorance can exist with education. However, I believe it's fair to say that it is less likely to do so, and this would at least weed out all the imbeciles.
Ultimately, a revolution is necessary. Some sort of ideological revolution that will change the way we manage our world. I believe that is clear.
One thing is certain though. The problem lies not so much in the economic and political models we use. But in man himself. Corruption is seen across ALL levels of modern society. Man seeks to benefit himself over others. We need to change our mind state, and shift our focus on the benefit not to ourselves, but towards the entire global community.
On the other hand, technology is rapidly advancing, to the point where it is truly viable to expect human-like AI within the next 30 or so years (assuming current scientific theories are correct). This is where I believe the ideal model for humanity stands. No matter the political model, be it democracy, monarchy, etc... Power corrupts man. Any man, no matter how good-hearted and honest you may be, with enough temptation and the right circumstances, man will succumb to sin and deceit (
http://www.youtube.com/watch?v=XBmJay_qdNc). Therefore, in my opinion, the ideal model lies with machine. It may sound far-fetched, and even like science fiction. But ideally, the best model to ensure the proper survival of humanity is to have a machine rule over man. A machine programmed to administrate and govern the laws of mankind with a Communist Economic model. However, how we implement such a system, and if it will even work is a whole debate onto itself, on that no longer deals with Politics and economy, but one that deals with the nature of Artificial Intelligence. Not to mention, there is also the question, of how we establish such a system on a global scale, clearly a radical change is needed to shock the world into change is necessary.
Either way, as hopeless as current times and as bleak as the future may seem. I still hold hope. Our current path and the changes that have been happening recently seem to be leading in that direction, however, only time will tell what path we ultimately take.