Given that they didn’t live 100 years to see what the body became, that’s a conclusion you can’t make. Fortunately, that’s why the framers gave us amendments to change what WASN’T working.
I have posted about eight vanities that looked at why the framers divided power between the states and feds, what federalists and anti-federalists had to say about government, and the ramifications of the 17th. I won't repeat any of it.
Tell me how the 17th better secured our liberty.
In the Federalists they asset the importance of the different bodies of government having different characters of design and influence. The 17th allowed for popular appointments of both sections of the legislature, which was against the founder’s well thought out design of government.