IMO the major flaw in democracy is .. complexity creep.
I'd say it is a root issue out of which several other issues arise. Make the banking system complex and you'll get a large proportion of people/voters, who can't be expected to understand the principles of it. Now if many voters don't understand the basic principles of something, politicians / rich individuals / large corporations can come up with intentionally (or unintentionally) wrong explanations of the system .. which allows them to exploit those people who don't understand the system.