Incredibly, author David Kruh compares the soul-less concrete wasteland of City Hall Plaza with the North End's pedestrian-packed Hanover Street. In today's Boston Globe, he writes: "As we look around the city at our experiments with auto-less streets (not just City Hall Plaza, but the mess that is Downtown Crossing) even the most anticar, pro-pedestrian advocate has to wonder if we are, once again, reacting with our gut instead of accepting how Boston actually lives, works, and plays."
Every streetscape, as well as street, has its own characteristics that make it succeed or fail as a traffic route and pedestrian draw. Comparing poorly designed City Hall Plaza (where an existing neighborhood was razed and hideous "modern" architecture deposited where it didn't belong) with Hanover Street is like comparing Route 9 with Newbury Street and expecting the exact same outcome if cars were banned.
I doubt you could draw many pedestrians to the Golden Triangle even if cars were banned, unless building siting, architectures and facades were substantially changed. On Newbury Street, though, pedestrians would naturally fill in the added space. That's because Newbury Street is already a great walking environment.
Kruh, who has written two books about Scollay Square, is certainly correct that City Hall Plaza was an experiment gone awry. But that's not because it's a chunk of space where cars don't go; it's because of a terrible design. Nearby Boston Commons and the Public Garden work very well as spaces where cars can't drive through.
In fact, Hanover Street is already a major pedestrian draw. I doubt banning cars will make it less so; instead, it would give pedestrians more space to walk and sit outdoors. The idea here isn't to create another City Hall Plaza by wrecking the existing neighborhood!
Given the local climate, walkers probably don't need the extra space from, say, November through February or March, and it's certainly realistic to argue that during the worst New England weather, it might be more beneficial for suburbanites to be able to drive close to their destinations than it would be to keep the street empty for people who won't want to linger outdoors on foot. But once the weather gets nice, a pedestrian plaza on Hanover Street will improve an already great streetscape that's a proven pedestrian magnet.