Uninspired, tedious, and insipid design. I can't think of one redeeming thing to say about it. The existing building is not pretty, but at least it is unique, at least it can make you stop and look. And it does this without being brash or showy.
I am so tired of glass boxes. This "reboot" is about the worst ones we've seen so far. It is tired and generic in a way the Seaport has managed to avoid. There has been no attempt to create an interesting form here, no effort to make it visually unique or appealing. If it weren't for the background buildings in that render you would never even know it's Boston.
The architect seems to have given no regard for context. I wonder if he/she even bothered to visit the site. Post Office Square is one of the finest locations in Boston. It is surrounded by respectful buildings that work together to create a quiet and "cozy" atmosphere. Regardless of scale they are all a little deferential, allowing the park to be the gem that it is. Say goodbye to all that if this monstrosity gets built.
Please, no.