OTSkyline and Boxter, you guys gotta be cray.
There of course is some things that could have been done different, but also remember, this is designed to be LEED certified, and windows dont usually lend themselves to efficiency. As for the mecanical penthouse, I think it looks pretty good. Kind of like a crown on the tower, not made of gold, but made of something more human, steel cladding.

Plus, if the did add floors to match the Mechanical, nobody would want to live there, it doesnt really lend itself to eing a high class condo living next to a mechanical penthouse.