Yes, but how do you keep the convention from simply ignoring the restrictions? Politicians don't like restrictions on their authority.
As I said, the Constitutional Convention was a "ruanway" convention that exceeded its mandate to amend the Articles of Confederation.
Congress could have said, "General Washington, we appreciate your hard work, but the convention has exceeded its authority under the Articles. We thank you, but we won't be passing the work of the convention on to the states."
But the situation was believed to be so dire that Congress swallowed hard and voted to pass the new document on to the states. Washington had just that kind of respect.
If the convention ignored the restrictions placed on it by the states' language, I would imagine that either a case would be filed before the Supreme Court, or Congress would ignore those amendment proposals that went beyond the purview of the convention.
The ABA looked at this back in 1965 and suggested that the Supreme Court be available to adjudicate on the spot any issues that came up during a convention.
When Congress determined in 1992 that the 27th Amendment, written by James Madison as part of the Bill of Rights, was now ratified and part of the Constitution, it also regularized the amendment proposal process. Only ratifications of amendments, or calls for a Constitutional Convention, that are "contemporaneous," meaning within a seven-year window, would count as valid.
The essay assumes that any such Convention would be a general one, at which the Delegates could propose whatever amendments they wanted to. This ignores the fact that the States control such a Convention. If the States call for a Convention limited to a particular subject, then Congress determines if 2/3rds of the States have also called on that subject. If so, Congress calls the Convention dedicated to that subject, and can refuse to submit for ratification anything which goes outside the legitimate subject matter of the Convention.
For decades now, some tin-foil hat folks have been using the lie that any Convention must be a general Convention to raise money from people fool enough to believe that. It is false, and I have now fought that false belief in hearings before committees of 26 state legislatures.
The fact that the same false belief has cropped up in this essay is unfortunate. If the subject is still live after the election, and I have more time, I'll join in this discussion again.