That's a very surprising take to me.
Some more obvious problems with the US constitution are highly ambiguous clauses (right to bear arms vs militias), unclear powers assigned to parts of the government (could Pence have legally decided on the electors to make Trump win? what's the exact succession of powers?), an election system causing imbalanced voting power (how many senators per state vs population, first-past-the-post vote), important rights left undefined (right to privacy vs the abortion issue), and many many more issues. These really are just the recent things that come to mind. These problems also don't seem scholarly, they appear to have substantial impact on political reality.
The US constitution was certainly a huge achievement for the 18th century. There's - unsurprisingly - been a lot of progress in constitutional theory in the 235 years after though, and it seems like it is a massive liability for the US by now.