something to do with city support infrastructure, and flow of human movement through and to a city... how a relatively isolated city is plugged in to larger networks and also feeds from its own interior networks? I don't know.
so this is still an early theory... but notice on the Waterfront City plan, the project is not only the gridded square island that gets most of the attention - there's also a part laid out like Venice, irrational and intercut by canals. The juxtaposition between these two urbanisms seems to suggest the relationship between Venice and its cemetery San Michele, an artificial, square, gridded island away from the main islands of the city... there are formal similarities: the number of blocks, the one missing corner, the relative placement of the cemetary axes and the green space, etc.
The placement of the "sphere" - a holdover from an earlier OMA project (and from Delirious NY if you wish) - in the Waterfront City indicates to be that the gridded island is literally a cemetery for old discarded projects, and by extension, for the NYC grid, an urbanism ill-suited to the demands of modern-day Dubai. (Note also that for all the benefits of the grid, it has never appeared this unscathed in OMA urban plans.
So, i suppose the thesis is that the waterfront city gridded island is a memorial to the grid, and to Manhattanism, much as Venice is a permanent memorial to itself....