I like the basic design of the tower, not a fan of what appears to be a pinkish hue to the stone facade, but other than that I think something similar would provide nice street frontage, although I would prefer continuous sidewalk engagement rather than the substantial set back in the middle.
Overall it would provide height, density, and street engagement while providing a non box design for a possible new tallest.
I do however like the overall concept that the newest developer proposed, or built. I think it provides a bit more variety and pedestrian interaction. If we weren't looking at the basic design as a possibility for the CCH, I would actually prefer the newest proposal as a better addition to a block/neighborhood. In the sense of a CCH thought, I think it's great.