The MI FairTax is Simple:
   NO Tax Filings
   NO Loopholes
   NO Hidden Taxes

Well, maybe.  

First there is that matter of a rebate to poorer families.  Some sort of filing is necessary, even if you don't call it a tax filing.  So there is a bureaucracy required.

Secondly, there is the issue of items being taxed that were not previously... food and services... that add a level of business complexity.

Thirdly, there is the issue of a National Fair Tax which is also proposed.  This, again, makes all retail businesses the tax collectors for Uncle Sam.

Nothing is ever as simple as it first seems.

http://taxprof.typepad.com/taxprof_blog/files/bartlett_fair_tax.pdf

That said, the current tax system is badly in need of overhaul.  At the Federal level, a flat tax would make more sense and could be modified with a standard deduction applicable to all income levels.

http://hallofrecord.blogspot.com/2010/05/taxed-flat.html

and

http://hallofrecord.blogspot.com/2005/03/excessive-spending-taxes-and-shelters.html

At the state level, all states and all internet sales would have to be taxed at the same rate or states with higher tax rates would be less competitive.  Good luck getting that to happen.

Florida and Texas have been pretty good models for having a sales tax without income taxes, but corporations still pay taxes.  Again, it is an issue of how much is taxed at which level and is it competitive with other states.