I am not sure if this is a crazy idea or not - there is a ton of bus traffic around the Duomo and the rest of town as it is - it wouldn't seem like the addition of the rail traffic (which would I hope cut down on some of the bus traffic) would make that much of a difference. It will probably be quieter and cleaner. And I have learned that the far right will exploit anything here to make some noise and get attention (for an example see the Amato story about the Da Vinci):
Florence, the city that houses a large part of Italy's - and Europe's - cultural heritage, is bitterly divided over plans for new tram lines that would slice through its famous Piazza del Duomo, the cathedral square. The first rails are to be laid next week as part of a €700m (£500m) scheme that would give Florence three lines, running for a total of about 12 miles. The second line would run from the airport through the cathedral square, the Piazza del Duomo.