Earlier quoted context omitted.
I think you're still stuck on W-2 employees (which is a pretty large and common case, I admit, and I'd love to see that simplified). You will always need accounting for businesses (IMO). Suppose you ran a lemonade stand. You bought some equipment, some raw materials, you used some utilities, you used some space, you bought a banner and some flyers to advertise your stand, you hired a lawyer to help set it up, you bou…
Sure. Let's focus on the individual return first. In terms of businesses, I hold somewhat controversial belief that businesses should not be taxed. Their employees are taxed, and people recieving dividends are taxed. By not taxing businesses, we'd also balance out the unfairness in the system today, where large companies are able to offset all profits with deductions, and small companies which actually pay quite a bi…
Your hypothetical "fair system" will have to have policies and regulations in place to deal with all of these situations.
As far as I can see, the only opportunity for real fundamental simplification is to completely drop all taxes on income, and substitute consumption-based taxes. And even that is not as simple as it sounds (how does it deal with barter, for example?).