First off, the article’s author is a bit of a moron, so no need to get too hung up on that.
However, I agree with many of the comments before regarding the fact that our open space is often underused. But I do think that much of society assumes that grass and trees are what open spaces are all about, so when we design in this newer way there is a certain amount of public education that has to happen (I am saying this in the context of the US and western Europe).
Having said that, I am beginning a research project looking at how vacant or underused spaces could be put to better use. I am focusing on a more urban situation (Dublin, Ireland) but in the wider context this might mean incoporating things like storm water attenuation or wind mills or other municipal treatment plants creatively into the traditional park landscape. This would help to begin the discussion about more sustainable methods of dealing with our waste, and help educate people like the author that we can’t just use all the water we want, not take some sort of conservation role regarding native plants and animals, and well not just assume that a Landscape Architect would solve the problem.
And lastly, while the hand rendered drawings of that park looks pretty attractive, it does seem as though the park is taken up primarily with attenuation, encircled by walking/seating areas. One would expect there was some degree of public consultation which identified a scope for the project, but you would also have to imagine you could have catered for more uses within that space while still serving its apparent main need as a attenuation facility.