They can't keep the 8th ave connection at grade unless they did massive renovations as the floor of the building and it's supporting structure are about a half storey up. The plaza is the easy part to fix, the back side is a different storey. My biggest concern is that the transients and vagrants that love the current libraruy will all move to 3st as there will be less traffic there, so the city should really try to do something on the 3st side of the municipal building. Not sure if they can create retail spaces on the back side, it looks like it may have been designed to accommodate, but there are likely offices or service spaces there.
If anyone is ever walking between Arts Commons and the Municipal Building, they have some old renders of some of the proposals for the building on the walls, right by where the parking cashier used to be. They definitely did not choose the best design IMO.