To spur affordable housing, Mayor Bloomberg wants to reform the city’s tax break for new residential buildings. But the mayor’s proposed fixes would only further distort New York’s already distorted property market, without lowering housing costs for average New Yorkers. The mayor would do better to push the state Legislature and the City Council to scrap the convoluted tax break altogether. The savings could then be used to cut taxes across the board on owners of apartment buildings, condos, and co-ops.