Complexity problem 1: Wealthy people can afford lawyers and accountants, who exist entirely so that money can be made off of the complexity of our laws. Unsurprisingly, this means that the well off are more likely to receive tax deductions &c. They report and record their income and expenditures more carefully and they have access to experts who can maneuver the many loopholes and edge cases in our current system.
This is compounded by problem number 2: As some of you may have noticed from this income and expenditure spreadsheet, education trends with income. That means that if you're not making a whole lot of money, it's likely that you don't have a whole lot of education or training in order to deal with the complexities of tax law, which means you probably wont be able to do as good a job as a highly trained professional expert tax payer like an accountant. Surprise!
I'm not the first person to have noticed this, as you can see from Obama's recent budget speech, but I hope this expresses the issues succinctly. Basically, I think tax payments should be a simple function of your income. We should be adjusting the level of taxation to what we expected to make on average at each income level once deductions were applied, and we should leave social policy implementation out of our revenue stream. This would have a whole pile of interesting side benefits like:
1. Taxes would be hilariously easy to calculate for people with regular salaries, which means the government could just send you a bill rather than forcing you to wade through a pile of inconvenient forms. I'd love that.
2. Human beings might understand the tax code.
3. Politicians wouldn't be able to sneak in weird policy ideas under the guise of tax breaks.
4. Our revenue stream would be highly predictable on account of no variance being introduced by lawyers
5. We would put huge numbers of accountants out of jobs (Hurray!)