We have several problems with our elected officials.
For one, we have people who make a career out of high office, senators and congressmen (and women) there for years. This not only promotes stasis in government, but isolates them in a DC "bubble" from current cultural changes and understanding of (for instance) technology - the same things they'll be called on to regulate. Strict term limits will force a turnover and help keep our representatives representing US.
Another issue is the strength of lobbyist and industry money. While I would prefer public financing and an overturn of Citizens United, one other issue is the promise of lucrative industry and lobbyist jobs upon exiting office - thus buying the politician. Restrict these from being taken for 3-5 years after leaving office.