1. I agree that the streets should be two-way regardless of the courthouse situation. It's proven that this is good for economic development in downtowns throughout the country and a great example in Florida is Lakeland. They got rid of most of their one-way streets a decade ago and the rest has been history. With this in mind, simply two-waying streets will also eliminate any traffic concerns.
2. Greater than pedestrian traffic on Monroe is pedestrian traffic and interactivity along Adams and at the base of the courthouse garage. If Adams can be rebuilt in a context sensitive manner (it has to be rebuilt as a part of the courthouse project), it can easily become an environment where the green space is lined with street level retail and outdoor cafes. That type of pedestrian scale interactivity will draw more pedestrians to the area, making forcing a new street into such a space more questionable than it is today.
3. Pack the green space with special events and activities. Go throw a frisbee, play pick up soccer, have a concert, festival or protest in that space and brand it as a public space. If it's used, the argument for forcing a street into it becomes more difficult to push.
4. From my understanding, Mayor Brown did support this bill.