The reason why U.S. taxes are so complicated is because every special interest group wants their one line item deduction. And when they can't get a full deduction, they'll accept convoluted computations for partial deductions with a cap, so now it's a worksheet to do the computation for the actual deduction. Multiply that by every goddamn special interest and you get a 15 form submission every year.
Income tax should be a single form for everyone. Progressive rate. No deductions for anything. No home mortgage deduction - your mortgage interest is not a superior benefit to all of society than someone else's marked up rent. It's a special interest hand out.
The only fair way is if it's the same for everyone.