Great photos. You captured the skyscrapers nicely. Especially love the angles caught of Book Tower:
It's a shame though that even in the 6 years I lived close to Detroit, the city lost 3 very significant and large downtown buildings which are just windswept empty lots in the foreground in a few of your photos. At least 10 notable midrise structures were demoed, and two of those pre-war skyscrapers have closed down and become abandoned recently. It may not seem like a lot to someone from NYC, Chicago, Philly, SF, LA, but downtown Detroit is very compact, and the number of buildings can easily be counted. Detroit is at a critical moment where any further loses of vintage building stock may endanger the core's architectural value and aesthetics.
There were a few minor gains in the past couple of years, and one major being the Book-Cadillac renovation, but it seems like it has always been one step forward, two steps back for downtown. Hopefully more renovations will gain momentum such as the Broderick renovation. Downtown Detroit still has a lot of valuable building stock as you can see and can become well positioned to having a once-again vibrant downtown.