More progressive, close the loopholes, fund the IRS properly so they are actually able to prosecute tax cheats (usually wealthy), set a cap on tax money that can go to the military and outlaw any tax cuts that primarily benefit the top 3 tiers within 3 years of an election.
Then the solution is to make the existing income tax more progressive than it already is, not just throw it away.
More progressive, close the loopholes, fund the IRS properly so they are actually able to prosecute tax cheats (usually wealthy), set a cap on tax money that can go to the military and outlaw any tax cuts that primarily benefit the top 3 tiers within 3 years of an election.