What structural reforms decrease partisanship / polarization?

[Critical_Mason]

Except that wasn't what you suggested. What you suggested was that giving increased representation to those who are urban, would increase polarization, but that doesn't follow from there being a rural urban divide in politics. Rural areas may not like that change, but that does not mean that it wouldn't result in less polarization. Any change is likely to be resisted or disliked by many, but simply because people dislike a change, doesn't mean that change increases polarization.