I think Marion Street is not being used to it's full potential primarily because of it's designation as a transitway. Now I do not spend any time downtown during the work hours, so maybe someone can enlighten me. How popular is that bus route? Does it merit a dedicated street to bus transit?
The street, I think, is the most tree covered out of all of the downtown streets. Ideally, this could be a vibrant street with retail and dining. There are alot of people magnets along the way like office buildings, churches, government buildings. I think allowing 2way car traffic throughout the day on a brickstreet would help give the area and any future destinations more exposure. Since Marion Street doesn't really go any way north of downtown, I don't think it would have heavy thru-traffic. It seems to me that this street has a lot of potential of being a vibrant pedestrian-friendly corridor.
Something along these lines would be good...