I think a distinction needs to be made between the "ideal" and "the reality."
Ideally, a representative democracy has a lot of really strong points - and in reality, some of these do show through. I stress some.
The reality however, is that we are the issue of a sinner (Adam), and even after Holy Baptism many of the side effects of this remain, in need of constant combat.
For a democracy to work, those who are enfranchised (in the case of the modern west, all citizens over the age of 18) must be reasonably informed about both the issues at hand, and the real qualifications of any candidate putting himself in the running for office. Also, for a democratic state to be just, it's electorate must be just...otherwise a democracy breaks down and simply becomes the tyranny of the wicked majority.
Instead, what typically happens is that you have an electorate that often doesn't bother voting to begin with - and those who do are often persuaded by superficial considerations (ex. "he's a good speaker" or "he's handsome") and let their avarice be taken advantage of (namely, the classic strategy of professional politicians to bribe the people with their own tax dollars.) Indeed, politicians know full well that if their platform was completly honest (ex. "hey, our coffers are broke, so I'm going to have to up taxes and reduce certain services for the time being until the books are in order" or something like this) they'd never get elected.
Then there is the obscenity of how monied interests play into all of this. To become a real contender in national politics requires quite a bit of financial backing - which always comes with a price. Let's face it - it's bribery, round about bribery. Is it any surprise that in America, a country which allegedly views monarchy, royalty, aristocracy, etc. as anathema to it's values, that by default there has developed a sort of "monied" aristocracy, and "monied" political dynasties (as the current President makes very evident)?
Hence, cutting through the idealistic baloney, for practical reasons I'd prefer a monarchy of some kind. Not that there is no downside to this; but a bad king, imho, is still better than the conceit of being "free" in a system which is really in the employ of the privileged few anyway.
