There's no such thing as a pure economic system. Huge economic disparities existed in Communist Russia, and every first-world country has social programs in one form or another. Arguing for one system over the other is purely a mental exercise. Further from that, anthropomorphizing these systems (evil communism, anyone?) is both ridiculous and counterproductive to any form of free thought or progress.
It might be better to ask what the primary purpose of the economic system is (or should be). Once you know that, you can ask what we want to avoid when implementing the system, and what we want to encourage. You could say that the purpose is simply to maximize production. Or maybe it is to maximize the wellbeing of the people within the system. Maybe it is to create a system that maximizes both of these in a sustainable way, or maybe it is something else entirely. The system that you want in place varies greatly depending on what you think the purpose should be, and a different combination of capitalistic and socialistic policies is necessary for each.