Restaurants and kiosks? No seriously. These pictures are when it was STILL UNDER CONSTRUCTION. And it's winter. The trees are there.
Anyway, as to the difference between buildings, it's an important part of urbanism. It's very difficult to get really good pedestrian urbanism out of buildings with such large bases. To be really pedestrian friendly, a building cannot be too wide, and if it is, then steps need be taken to minimize the appearance of its width.
This picture and
this picture are similar angles of two blocks in the same neighborhood. They both show buildings that greet the street and have ground floor retail, but the first is a much more enjoyable pedestrian experience because the constantly changing storefronts present pedestrians with a continually changing (and therefore interesting) view. The second block very quickly becomes boring if you’re walking along it, despite retail.
Good urbanism - good pedestrianism - is messy at the ground level. The cleaner you make it, the less interesting it is. That Rockville attempts to break up the width of its buildings is a major part of why it's superior to most other new urbanist town centers.