I think the 17th amendment was well intentioned but wrong. That said its never going back to the way it was which in the end is all that matters. What it did was untether the Senators from direct interests of their states. What I’d suggest would be more doable is to reduce Senate terms to match House members it would force Senators to be under increased scrutiny and cause them to be more responsive to their constitutes.
While I agree that the 17th completely changed the Founders’ idea that the Senate represented the states (that’s why treaties are ratified by only the Senate) as I understand it, in 1913 it was believed that the rich and powerful within each state could easily buy the votes of then low-paid state legislators. The people of the time could not imagine that a majority of voters in a state could be bought off or influenced by big money to vote for a particular Senator. This was of course before radio and television ads would flood people’s homes for months before an election—paid for of course by big money.