As for the building, ironically it appears like something out of Indiana Jones, the last remnants left behind by a ancient civilization. Try to interpret it by focusing on the outside, but like a dead language it’s unreadible. It showcases it’s new “Terminator” style featuring the revealed metal endoskeleton infrastructure covered with organic material. Passing this off as “gardens-in-the-sky” to greenwash. As if anybody on the street would benefit from the supposed garden effect. After the Meiji restoration Japan began a rapid process of Westernization which led to the need for new building types such as schools, banks and hotels. The Japanese government also invited foreign architects to both work in Japan and teach new Japanese architects. One of their own architectural attempts was called Giyōfū which led to gems like these.

http://upload.wikimedia.org/wikipedia/commons/d/d4/Former_Kaichi_School_2009.jpg

First of all why do you separate green features and the building, it’s architects job to solve all the problems he faces in the given surroundings and combine all of it into a clear, relevant and working solution.
You say that if one takes all the plants off the building it will look not so visually attractive, maybe so, but plants were part of architect’s response, it’s the same as saying, what if i took car hood off it would not be ‘aesthetically pleasing’.
If do take the hood off what you’ll see will be not aesthetics but functionality, same for the buildings…