Mahloqet served as an internal self-critique mechanism. Pluralism serves this role in the modern world. It serves as the self-corrective to all tendencies to absolutism. Pluralism does not require any abandonment of party or school of thought or any diminution of commitment. Nor does it require any admission that the other view is right.
Pluralism is an admission of one's own limitations.
Only if you are perfect and your method is perfect and you are always perfectly sure is pluralism superfluous. But perfection models do not work, they destroy others and ultimately self-destruct. Far from weakening Judaism pluralism is a commitment to a Judaism that is ahead of ourselves. This will be a challenge for all. But Jewish pluralism, while requiring toleration, should go beyond it to include celebration.