Riversize Plaza barely seems to exist as a street or anything beyond a cartographical hiccup. I think it means
here (Google Street View), or Randolph and the river.
Sounds like they want to do the same thing as River Point: build a platform over the Amtrak tracks and build a tower on top of that. Depending on how big the parcel is and what the building plan is, its river frontage could — right up against River Point's.
Alderman Reilly seems to want them to take advantage of that fact and provide some type of public riverwalk plaza, like River Point is. It'd be great if they could be connected into one cohesive plaza under Lake Street. This would be right across the water from the new Riverwalk project, too.
The river area seems to hold a lot of promise, as others have pointed out.