That stuff is actually pretty good. San Andreas' large map canvas and a rich library of objects can be used to create some really stunning things and enhance the environment. It is very easy to make good and innovative maps, but there is always the question of performances on the server/client sides, testing and the actual will to do so. Not to mention that lots of map proposals get denied because they are made for a particular group of people, and not for everyone. Nevertheless, the video is very good and whoever made it knows his job.