Your high wealth clients -- do they get taxed on income, or on the basis of what's accumulated? I assume its on income for the year.
What our progressive system theoretically recognizes is that ability to pay ought to have something to do with the taxation system. That is, if there are three people earning $50,000, $500,000, and $50 million respectively, and if we need $1 million in revenue, then we can't take it in equal amounts from each person. Nor would it make sense to tax at the same rate for each person because the effect on the lower income earner is magnified given the basic costs of existing in our economy.
Having said that, I completely agree with the premise that the tax code system is a complete mess and out of control. We give tax breaks and incentives supposedly to encourage spending and investment in areas we deem "good," but it ends up just being a giant shell game. I would agree that needs to end.
But if you want to scrap the progressive income tax system for something like Neil Boortz' flat tax based on consumption, people need to think long and hard about what that will do to spending and the placement of dollars in the world economy.