Cutting the corporate tax rate wont do anything... unless you take away all the loopholes. The problem in the US, is the whole tax system is designed to be complicated to confuse and is in reality a reverse progressive tax system where the rich pay the least in % compared to the masses. And no a flat tax is certainly not the solution and would make things worse.
This is of course a problem across the western world, but it is not as bad as in the US.
The first thing that should go, is capital gains tax of any kind. That kind of profit should be taxed as normal income or as corporation tax.
The personal tax rate should be progressive.. the more you earn, the more you pay in %. In stages of course.. so the first 30k is 20%, 30-50k is 30% and so on.
Most deductibles need to die... only the standard deductible really needs to say.. say the first 10k of ones income is tax free or something like that.
And a thing I really want to see even in my own country, is an itemised tax return where it is stated that so much in % goes to this and that. That way the population can see what their tax money actually goes too. So for example, of the 30% taxes you pay, 10% goes to military, 5% to healthcare, 5% to SS, 4% to administration, 4% to other or something similar.
Also the first law that needs to be passed in the US, is that SS needs to be paid back fully and future administrations are banned for taking out money of SS.