No sources but here is my firsthand knowledge at the time.

Stucco provides an extra layer of durability over brick, it stops molds, it halts deterioration of brick and can be painted to create a uniform look within the city. Brick by itself can be very esthetic however you need professional bricklayers to a) lay them properly and b) point them so it creates a visually pleasing look. 

Up until the 60s and maybe even early 70s most commie blocks had stucco and paint. Materials were still not scarce and they could afford to do this. Certain commie blocks that were designed for the Chinese technicians that came at the time , even have marble bases and mounding design patterns on top. You can find these in cities like Gjirokastra and Tirana. 

Late 60/ and early 70s materials became scarce, this resulted in initially exposed brick commie blocks. These were still built by semi skilled workers, and the brick doesn’t look too bad (although it clearly not done by professionals and looks terrible by western standards)

In early 80s shortage of materials was combined with shortage of these semi skilled workers which resulted in “voluntary work” (pune me kontribut vullnetar). This meant that if you wanted an apartment you had to build it yourself along with the others in that complex. The party would assign the engineer that “oversaw” and gave you all the equipment and materials and people built their own commie blocks. These are by far, the worst buildings in Albania. Although structurally they may be (for the most part) sound, visually they are an abortion. The construction is very shoddy, bricks are not pointed or aligned and they are clearly crooked. 

It was a very difficult time and exposed bricks were the least of peoples problems