That's a good article, addressing the two underlying, unspoken issues of (1) Bush administration's stonewalling the investigation of the disaster and (2) the rush to redevelop for purely commercial reasons. The press usually "critiques" the designs without weaving these into the discussion (well, maybe a bit of the latter, but never as a fatal flaw). Also, I hadn't really thought of this:

Walls of falling water in an open pit and without glass barriers are a problem, especially in inclement weather. Wind (and the area tends to be windy) will spray water on visitors as they try to take rubbings of names on the walls. In the winter, the waterfalls will need to be turned off; if heated, they will cause a frosty mist. In short, there are a host of problems.