Conceptually, it works as intended:
Bowie, from the perspective of those who worked with him and loved him. And there is more joy than sadness here.
No fluff, no glorification, just a true to life account of a creative genius' last 5 years, true to himself until the very end.
You will never get a full picture from Bowie. It's up to you to figure out the puzzle, and it's beautiful.