The solution to "fixing" the U.S. Senate is to repeal the 17th Amendment...
Bingo! What was orginally intended was one house of the Congress would represent the people, and the other house would represent the States. That's a good plan, and we should get back to it.
If the Senators owed their positions to the States (via the legislatures who appointed them) instead of to their ability to dole out federal funds to the people, we'd see a lot less power concentration in DC. Can you imagine, for example, the States (through Senators who truly represented them) approving Justices to the Supreme Court who are so fond of usurping power for the federal government? The 9th and 10th Amendments would have meaning again!