1) Fica hasn't been included
I don't think it should either unless you are also going to include future benefits as well. This is, or should be separate from the general operating fund of the government, despite the present practice of "borrowing" from SS funds. As well, there is a cutoff as to how much FICA one pays precisely due to there being a limit as to how much one can collect. So, to compare someone over the cutoff to someone below the cutoff is not valid. If SS retirement collections were unlimited, then a comparison could be made. Remember the purpose of Social Security - Supplemental income.
2) It's based on reported income. Sure, the people that have the highest Adjusted Gross Income are going to pay the most taxes. But if you have someone who made $1 million, has $600,000 in deductions, he'll be listed as having $400,000 in income, not $1 million. So the entire calculation is faulty.
This might be true except for a couple of things; first, I doubt if there are enough deductions avialable, year after year, to reduce a $1 million income to $400,000. If you're talking business expenses, well then that's another story. But, remember that business taxes are generally passed on to the consumer anyways. And business expenses are a necessity.
The other issue is the AMT (which has never been adjusted for inflation BTW). There are plenty of people with much smaller incomes that have been hit by this little beauty.
Frankly, I'm with you on one thing here; there ought not be any deductions. Taxes are not the proper method to steer people's activity. I also think a flat tax is the best, most fair way to collect the funds necessary to run the government. And I think that Social Security ought to be voluntary, not mandatory.
No arguments about your position from me. Well stated.