Roxbury in general seems to suffer from the super block more than other areas of Boston. Probably because they are government projects and people used the latest idea. It is sad that one of the most beautiful areas of Boston, with such great natural topography, has been so badly abused. I hope as those developments age out they are replaced in a way that is more connected, per Whittier and Orient Heights.
Looks like that land was cleared for the interchange (1962). Obviously plans changed as Madison Park/Campus High UR was developed after the interchange was moved.
A small point of interest, I never understood why the small residential section along Melnea Cass had the extra side streets right up against the boulevard. Clearly they were designed when I-695 was still planned and they wanted to keep them separate from the frontage roads. It's a total waste of space today.