The diagram showing the evolution of the plan, using different zoning rules, is interesting. You can't just start with the tower you want to build, you have to start with an ugly lump, then mold it into the desired result.
How exactly are they planning to go from step 1 ("additional density") to step 2 ("reformation") ? It looks like they would have to demolish about 10 floors' worth of housing and rebuild it in the center of the lot. That can't be done overnight, and all those people whose housing you have to demolish would have to go somewhere.
I had the some question, but then realized I was misunderstanding the diagram. Replace the word "step" with "iteration" and it makes more sense. This is showing how the design evolved with additional constraints.