This article puts forth bold claims but no proof of such claims; as is typical in this particular subject of discussion. To say Senators picked by the state legislatures would be less politically driven than Senators pick by popular votes does not make it so. Knowing human nature, I am sure there were many Senators that were politically driven the first century of this country.
Claiming the states are more able to pick able senators than the people is using the same argument used in this article that Roosevelt used, that our betters (elites) are wiser than the people.
Why two popularly elected houses of Congress?