Yep, enact a flat corporate tax, BUT do away with any and all loopholes. A 20% corporate income tax, with no loopholes or corporate tax breaks would probably result in a net increase in tax revenue.
Corporate tax is a loser. It punishes the efficient and productive corporations and rewards the in-efficient via tax loss carryovers. And it increases need for tax loop holes. By weakening domestic corporations, we weaken them against foreign corporations.
If corporate tax is zero, there is no need for loop holes.
Also, corporations never pay any taxes. They pass it on to the customers, share holders and employees. Corporations are never final owners. There are always individuals who own or control every cent of corporations (share holders, CEO types).