2. Agreed regarding the Congress St side, though the added playground from [1] adds some interest to that side (before the solid brick wall part).
3. Agreed with the interior. Something like just changing the flooring or interesting lighting would make it feel less cold. The floor is either brick (I assume an homage to Boston's brick) or terracotta tile. As a very rare visitor inside, it's kinda fun to see how the decor/lighting/infrastructure works with all concrete (hanging things from the ceiling instead of nailing to a wall, for example)
[1] https://www.sasaki.com/projects/boston-city-hall-plaza-renov...