Wouldn’t that mean juries could only be made up wishy washy idiots who have no opinions on anything with goo for minds for the lawyers to shape? Actually, I seem to recall a chapter of To Kill a Mockingbird where Finch basically says that and why
Mark Twain said something pretty similar, I believe.
I would greatly prefer a system like UK’s, where you basically get a randomly-selected jury.
But since we’re stuck with our present system, I don’t think you want people on the jury who’ve already made up their minds about the issue in question before the trial starts.