While you make good points about the Constitution’s being amendable, etc, you do not seem to make allowance for even the possibility that it could be amended in a less than salutary manner.
Your best point is the difficulty in believing that career (state-level) politicians can be trusted to select better senators than are currently being elected popularly. That is a tough one.
More importantly, however, in my view, is that you fail adequately to take into consideration that, under the current (post-Seventeeth system), we the people for the most part really do not in any meaningful way “choose our Senators.”
Rather we choose between the two surviving big spenders. Virtually no one wins a state-wide election in a large state such as California, Texas, or Florida without running a campaign financed by tens of millions of dollars.
This is why you are — in my view — ultimately incorrect in your view. You fail to acknowledge that the senate candidates from which we are forced to choose today are put there — 90% of the time, anyway — by special interests. How is that an improvement over the pre-Seventeeth system?
Of the 10% of the candidates that are not put in play by special interests — let’s name three: Angle, Akin, and Cruz — most are mowed down by opponents who are backed byh special interests. For the exceptions, such as Cruz, we can all be thankful, but I think either system — pre- or post-Seventeeth — will occasionally pick an outstanding candidate such as Cruz.
I say: Repeal the Seventeenth. How can it be any worse than what we have now?