Instead of adding Amendments we should be repealing some. The 17th and the 13th should be the first to go.
The 13th Amendment prohibits slavery. You want it repealed????
The notion that perhaps a couple of Amendments should be repealed has no bearing on whether others should be added.
Over the past 100 years or so, the power and scope of the federal government have expanded by leaps and bounds, while no constitutional amendments have been adopted which are specifically aimed at reining in federal government growth (except perhaps the 21st - repeal of prohibition). Prof. Barnett deserves congratulations for proposing such amendments, which at the very least could start people thinking in the direction of constitutional changes to save liberty and repel centralized government tyranny.