Those "loopholes" are called the tax code and every provision is intentional and it is the way Congress dictates how we live our lives and how "companies" run their companies.   So in that regard the tax code could use a lot of simplification.   But regarding "companies" or specifically corporations, whatever rate you want to tax them it is individuals who will be doing the paying.   They should be taxed alike but for competitive reasons at a  rate comparable to other parts of the world with similar economic systems.   Presently, US corporate tax rates are excessive.