Current systems of taxation are complex, unfair to many groups, expensive to administer, and lead indirectly to much societal damage.
I suggest a much fairer way to operate the government and one which would place natural limits on government size and power:
Change the Constitution to only allow an estate tax of 75% and a personal gift tax of 75% (except for charities which will abide by strict rules). It would be limited to estates over $100k or gifts in a year over $10k.
If set up correctly to avoid loopholes, this system of taxation would naturally limit the size of government expansion and force politicians to more carefully prioritize and monitor government spending.
The estate tax also helps to eliminate one of capitalisms unfortunate side effects- rich kids who dont deserve inherited wealth.
Also put in place would be strict rules disallowing the government from taking on debt. Force politicians to live within their means and not to build careers on the backs of tomorrows children.