In a socialist utopia you have more democracy than in a capitalist utopia, because "true" socialism gives workers democratic control over their workplace, where as "true" capitalism gives full control of the workplace to the capitalist.
Indeed, democracy is better at preventing corruption than dictatorship.
Are you suggesting capitalism is not supposed to give control to the capitalist? Or that socialism is not supposed to give control to the workers? I thought my assessment was pretty uncontroversial. The point about which system yields "more" democracy is a pretty simple inference from there.
Or do you mean my last statement that democracy prevents corruption more than dictatorship? What do you propose we measure to verify or reject my hypothesis? No amount of data can prove it. But there's a pretty clear argument in favor of democracy: you can't stop corruption in a dictatorship if the dictator is corrupt; you can stop corruption in a democracy so long as the majority are not corrupt. A dictatorship can have close to 0 corruption or close to 100% corruption, it all depends on the dictator.