Each branch is supposed to check the other, but that doesn't happen either. So I guess you should just rewrite the Constitution and this new, perfecter system will resolve the need for unexpected problems to be resolved by a court.
The SC has obviously made numerous errors, but your expectations of a Constitutional Convention are both incredibly dangerous and, more importantly, not going to have the result you imagine. Do you sincerely believe that a government of millions people can write law so perfect and consistent that there will be no need for a small group to figure out what it means? What is the alternative here? You dislike Roe v. Wade because you believe it invents stuff out of whole cloth - show me a Supreme Court ruling that doesn't do that.
If that is what the Founders had in mind, they were more foolish than I thought.