I thought it was worth it to post a link to the actual proposal the city is making, which isn't available through the link I provided a couple weeks ago. What's interesting about this proposal is that it looks like it is trying to relocate the core of the square. For those familiar with Union, activity is centered on the north side of Somerville Ave and around Bow St.
By proposing to demolish around 30 buildings (some of them quite large), the city envisions essentially building four large blocks of a major commercial center from scratch - and relocating the center of development in the square from the intersection of Somerville Ave/Prospect to Prospect/Webster, which is currently a wasteland.
http://somerville.patch.com/article...or-redevelopment-of-union-square#pdf-11040113