If an important goal of the tax code is simplicity, it's a major failure, according to a survey from personal finance website WalletHub.

More than 80 percent of the survey's 1,086 respondents deem the tax system as complex or extremely complex.

The study also found that:

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• A total of 44.2 percent of the respondents think the most just tax code possible would have fewer deductions than exist now.
• A total of 90.7 percent of the respondents maintain that investment income should be taxed at a rate at least as high as wages. A total of 57.6 percent believe wages and investment income should be taxed equally, while 33.1 percent believe investment income should be taxed at a higher rate than wages.
• Americans view taxes on wages and gasoline as the least fair and taxes on alcohol and tobacco as the most fair.
• The respondents see tax fairness (61.2 percent) and tax equality (20.8 percent) as more important than whatever is best for the economy (18 percent).
• A total of 65.1 percent of respondents want corporations to pay a higher tax rate than individuals do.
• Only 24.3 percent of respondents favor a flat income tax.

Meanwhile, French economist Thomas Piketty, who has created a global stir with his new book, "Capital in the Twenty-First Century," says the wealthy should pay higher taxes.

"If you have a progressive tax on income and wealth, you have a better sense of who's paying," he tells CNBC. "And you have a better sense of where the money is going, and whether you have an equitable distribution of the burden."

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