Eliminate corporate, capital gains, and estate taxes. Remove wage income cap on Social Security tax.
Are you really OK with an 18 year old who inherits a $100M investment portfolio outside of retirement accounts and never needs to do any W-2 work never paying any federal taxes at all in their lifetime? IMO, the reverse scenario where W-2 work is untaxed other than for social insurance and passive income is taxed heavily at 25% or even 50% from the 1st dollar is far more just and efficient at promoting work.
*I presume you are including taxation of stock dividends and (non-municipal) bond coupon payments in "capital gains." My apologies if you are not.