Capitalism has created more wealth for more people in more places than any other economic system. But what could we change to make it better? The single biggest improvement I can think of is the elimination of fractional reserve banking.
Fractional reserve banking is essentially legalized fraud for the politically connected. All banks in a fractional reserve system are by definition insolvent. This is what led to the frequent panics of the late 19th and early 20th centuries. To try and stabilize this we institute a central bank. This in turn allows banks to maximize their leverage, growing the money supply faster than natural currencies can grow, necessitating a fiat currency and causing inflation.
At this point it becomes clear the arguments of bankers are circular. We need fractional reserve banking because we need to grow the money supply. We need to grow the money supply because we have a central bank which allows banks to issue loans exceeding the money supply. We need the central bank to prevent the collapse of our banks because we have fractional reserve banking.
Inflation and the artificial growth of the money supply lowers the cost of debt and imposes a cost on savings. This causes an expansion of debt and insufficient savings leaving us ill prepared for hard times. It increases the level of consumption causing our economy to put extra stress on our environment. It fuels the growth of bubbles, including debt bubbles. And when the debt bubbles collapse we get depressions. It causes the concentration of wealth and the corruption of our politics.
The elimination of fractional reserve banking would in one stroke eliminate or mitigate many of the most common purported failings of capitalism. But they are not the failings of capitalism. They are the failings of a fraudulent banking system.