I would expect this development to come once the second phase of the railyard development begins to take shape, or at least after the first phase is well established. For the money they plan to spend on this tower, it will have to be very high end. They will draw on the popularity of the High Line, where multiple developments have had success by proximity, and a more established Hudson Yards.
We know with SHoP buildings, the facade can get very interesting. So besides the form, I would like to see what materials they are talking about using here.