I just ran the course yesterday so I feel I can provide some details missing from this thread.
The first 2mi loop that is only run once has 11 90 degree turns.
The 6mi loop that is repeated 4 times has 20 turns and with the way the side walks shift directions you could call it closer to 24 turns per loop. Conservatively it's 91 turns with those running it probably feeling more like 100+ turns over 26.2 miles.
During the 6mi loop mostly all the turns are condensed over a very span on the USC campus and Exposition Park. This section of the course is also ran on a lot of brick "walkways" that have narrow paths compared to roads and sharp turns since they weren't designed for traffic. There is no doubt that runners practicing on rail trails or other long straightaways aren't going to be prepared for the 2 miles of constant rythm breaking turns. Once you leave the USC campus it's all uphill back to the Staples center on a road that's completely straight (the final loop is going to be interesting with the final miles at a steady uphill) for what seems like close to 2miles.
There are three big turns within the last 400 meters including 1 complete U turn and 2 90 degree turns. I would have liked a better finish set up where the athletes aren't weaving around barriers but it looks like they didn't have a lot of options.
Overall there aren't any steep hills which leaves the main antagonist the 100+ turns over the course. I think the race is going to be slower than the race directors are hoping because of the turns forcing the athletes to speed up and slow down constantly. Id like to see a map of the Rio course and if it has a lot of turns this will be a perfect race course.
Another factor that may contribute to tough conditions is a high sun and warm temps. I ran the course at 10 am and it was already in the 60's which isn't uncommon here and by 11 the sun was well above us heating up the road temps. With just normal conditions I'd expect the race to be run around 60 degrees and having the sun above the runners will make it feel more like 70's.
It's a championship race and it'll be very spectator friendly. The runners are going to be pretty beat up after this race due to the turns and most likely warm temps.