A way to change the minimum strength requirement, but still keep the strength meter, and not let in Very Weak passwords, is to add the code from this script https://gist.github.com/BurlesonBrad/c89a825a64732a46b87c to your functions.php file, or to a plugin. It will keep the strength meter, and still enforce a minimum password strength, but you can reduce it to Weak (1) as the minimum, rather than Medium (2), or Strong (3).
