It was one of the hallmarks of the progressive era. It is a breakdown because it gave the Federal government more power than what the original framers intended. Just because something changed doesn't mean it's for the better. Ask Coke how that change worked for them.
The only intentions of the original framers that are relevant are the words that they put in the constitution. The con of original-ism just means "I'll pick some quotes I like from a select few of the framers in order to justify the position I want."
And what they intended is for the constitution to be adaptable. Because they couldn't predict the future.
As far as the 17th giving more power to the federal government, you're obfuscating the actual power exchange. The direct effect of the amendment was to take the power to choose senators from state legislatures and give it to the people of the state. This country certainly doesn't need gerrymandered state legislatures to have direct control of senators.
The idea that a person that lives in a rural area should have more power than a person that lives in a city was a necessary compromise to create this country. It has little value today.