Why do you think that a sales tax is less prone to corruption and complexity than an income tax?
When the income tax was originally promoted by William Jennings Bryan and other populists it was labeled as being fairer, since it would not hit the poor. When initially implemented it was very simple. However, over time special interest groups were able to lobby for exemptions, deductions, and other special treatment. Why would a sales tax not undergo the same process? Does the fair tax somehow magically abolish selfishness?