It would not hurt to try it out to see how it will effect businesses and parking.
Close it from Jefferson to Main St.
If they make a change, they should allow limited vehicular access, similar to the rest of 8th Street.
If the merchants along this section are in support of no vehicles, then trying it for 90-120 days would be a good litmus test. It isn't quite as pedestrian intensive in the dead of winter. Maybe closing it to vehicles spring, summer & fall makes sense, then reopening it in the winter. Might be a nice compromise.