The 16th and 17th Amendments didn't give Congress new powers that they essentially didn't already have.
As I ranted in my previous post, the reason that the Constitution is "broke," as you put it, is because many generations of parents have not been making sure that their children are being taught the Constitution, particularly the Founding States' division of federal and state government powers. Consequently, low-information voters don't understand that the federal government is wrongly making laws, such as Obamacare, based on powers which the states have never delegated to the feds via the Constitution.
Look if you really "feel" that way we have nothing to discuss. The progressives of the early 20th century knew what they were doing, how to destroy the republic, and their useful idiots still exit today.
The 17th amendment took off the leash that restrained the Senate. The de facto power that the Senators got was longevity.
And a campaign warchest worth millions in influence of others.
-PJ
The campaign warchest is not a trivial thing. Senators in "safe" states use this money to fund sycophants in the House through campaign donations. That is a powerful power from the 17th.
Eliminate the 17th amendment, and you eliminate the need to raise campaign funds, since the elections go away. It will be harder for Senators to be kingmakers.
-PJ