I would support Paul Ryan's original promise that 'you can file your taxes on a postcard'. With the caveat, every other person and corporation also files their taxes on a postcard.
This, of course, strips a fantastic amount of subtlety and control. Subsidize what you want and tax what you don't is standard tax policy.
On the other hand, i prefer scheme to c++. so simple as to be completely transparent is better than fabulous complexity. But, it turns out that's not a particularly popular world view.