If the founders were great and they kept their company growing they would not need the dual class share as the shareholders would have kept them at the helm. When you sell the majority of the equity in your company to the public but set up a dual class share structure to keep you in control and then you die leaving untrained and possibly qualified children in control is it fair to anyone.

If you want to keep control then only sell 49% of the outstanding shares. One share one vote.