Well... once Hyatt has the resources to go through with the renovation, I'm pretty sure they will follow that plan. It WAS exhibited as part of the Massive Change exhibition, but everything I've read about it refers to the design as an
actual plan for Hyatt expansion. The exhibition was only 5 months ago, remember - it's not as if it is some dead plan that was seen briefly 4 years ago.
Oh, and the caption for Massive Change also says that Gensler is working on a master plan for the rest of the riverfront from Columbus to LSD, including a "Green Market" for the city. This seems more fanciful to me. If you want to see a nice plan, go to Gonzalez Hasbrouck, which designed a plan (shown below) incorporating townhomes and a large deco building built between the disconnected Upper levels. I'm pretty sure this plan is speculation, though..