Proportional representation shifts power back to voters across the country and limits the ability of parties to win majorities with shrinking support. It strengthens accountability and reduces regional divisions.
Those with the money and power don't want that tho ... they don't want a democracy (a system run by the people) they want a plutocracy (a system run by the wealthy)
I think the first step towards changing the system of voting is to first admit that we don't exist in a democratic system.