Repeal the 17th!
Let's face it, today there are no real checks on federal government power. Congress and the Executive does whatever it wants, and the Supreme Court does nothing but provide them cover. The federal government is now a government of unlimited powers. But it wasn't always this way.
In the original design of our representative republic, there was an effective check on congressional power through the state legislatures' power to appoint (and remove) Senators. But the passage of the 17th Amendment in 1913 (the same year as the 16th Amendment (income tax) and the Federal Reserve Act), the state legislatures' power to appoint its Senators was eliminated, thus changing the fundamental structure of our government, and expanding federal control in every area of our lives.
Repealing the 17th Amendment would reinstate the states' proper relationship to the federal political process, and also have the effect of increasing the importance of the individual state legislatures. In other words, "we the people" would be more focused on our states, rather than on the federal government. Because with state legislatures appointing the Senators to represent their state, they would then have direct influence over the selection of federal judges and the jurisdiction of the federal judiciary.
So we would be focused more on our states (where government affects us most), rather than on the entire nation (of which most of we'll never even visit). No more "one size fits all."
Repealing the 17th Amendment would also greatly help with the problem of money in politics. With the attention placed on state legislatures instead of the federal government, lobbyists would lose a significant amount of influence. It would be much more difficult to lobby 50 state legislatures than just one in Washington DC. Also, it should be obvious that Senators appointed by the state legislatures wouldn't need to finance a campaign.