The election process is designed around money, advertising, rhetoric and mudslinging. The result is those who get elected are often the best at the election process, but they may not be the best for the job, since this is two different skill sets.
As an analogy, say we change the election process to be more like a mixed martial arts tournament. The person who wins this process will become president. The winner of this process will be someone who will be the best fighter. However, being the best fighter may not translate into the best person to run the country since these are two different skill sets. Many good people, who would be good leaders, will not even try because they know they can't compete in the process. One round of mudslinging would knock then out with the powers to be able to do illegal things to get dirt. It is not so much the people making a bad choice at will, but bad choices, by default.
A democracy would be better if the election process was designed to end up with the best people for the job winning. This would eliminate grid lock and other forms of treachery needed by people in power, who lack absolute power, while not being the best for the job.
The current election process has the advantage of making it possible for all the masses to participate. If the process was done in a purely intellectual way ,to choose a qualified leader, this process would lose most of the people,who do not relate well to egghead stuff. The mudslinging and rhetoric, appeals to people who like to gossip and watch fantasy on TV, allowing them to participate. It is not easy to design a process that picks the best while appealing to all levels of understanding.
One change that could be made is the media is often biased for different candidates, with parts of the media biased to each side. At the same time, the media makes a lot of money with campaign adds. One way to make a change of the better would be to call any media bias, a campaign contribution, valued at the time rate they charge for candidates to advertise. There are campaign contribution limits in the law, and if they exceed these limits, they break the law or anyone can break the limit law. This was the press will not become the propaganda wing of any party, but a more balanced source of information for all. This does not limit free speech but obeys campaign law like all businesses need to do.