You're missing the point. The indexing lacking in AMT is the indexing for INFLATION -- it is NOT fair that a tax originally meant to make sure "rich" folks paid -something- ends up hitting middle-income people, for whom it was NEVER intended, hard. But the gutless weasels in Washington don't have the testicular fortitude to fix it, because it brings in cash. So we get the annual "patches" (to stick another temporary finger in a very leaky dike) that are put in only so they keep from getting run out of their home towns on a rail.
And I support the FairTax, not a flat tax. I hear railing every year from Massachusetts taxpayers about the unfairness of the state income tax. I always point out that it's a flat tax.