When I worked for a small city in Kansas, Wal-Mart used what is referred to as a "micro-forest" landscaping concept, which consists of using larger landscape islands, as opposed to say, one island for every ten parking spaces. It worked out nicely and still looks great! They used a lot of transplanted trees, instead of the two-inch twigs that usually die. In terms of landscaping, I would put that Wal-Mart against any other that I've ever seen. I would highly recommend this method of landscaping.
In many of the projects I work on, we advocate for fewer islands that are larger. Even if the net square footage is the same, it makes for larger trees and shade. The 25 sqft islands every ten spaces will not support good tree growth. Often the problem with the larger islands is tree growth is usually so good it blocks signage. One client I have likes the small islands because he knows tree will keep dying and he can keep replacing them while maintaining his visibility.