Even a "progressive" tax could be made far simpler than the current nightmare of thousands of pages of tax laws and rules, each line of which was purchased from a Representative or Senator. The problem with the current tax code isn't whether it is one rate or a dozen rates - it is all of the deductions, exemptions and credits calculated before you can even look up the taxes owed on the tax table.
I personally would prefer the NRST to an income tax. A flat tax is a distant second, but still vastly better than the current system.
Note the point 4 in the original post. It sure looks like the number of filers is counted twice by including both the 1992 and 1993 tax years.