How might the amendment method of a constitutional convention be unpredictable?

Critics of the convention method often argue that a constitutional convention, by its nature, cannot be limited and thus could revise any part of the Constitution even the Bill of Rights if delegates were so inclined. There have been no more Constitutional Conventions since every single amendment to the Constitution has been first proposed by Congress and then ratified by the states. "One of the reasons we've never called an Article V convention is that the Constitution doesn't really tell us how it would work," Vile says

it repeats in the format of each sentence "the gods [blank]"

i also see that they are way better humans.