I am more & more convinced that congress is soo corrupted by its power to tax that should we hope to pertinently remove that power we will have to remove all exceptions, and demand true uniformity.
Although realistically congresses insatiable need for revenue can only be fed security by a levy upon a 3rd party who must determine how to raise that money. In our case our State governments are the most logical choice for domestic taxation, given their superior sensitivities to the domestic economy.
But the most honest system of all is to create individual tax liability accounts for every citizenry of every state, and call that account debt. Then create a uniform system by which that debt is repaid.