Tokyo, Rio, London were all very flat. Have they ever ran it on a not-flat course? I feel like that would make the race much more exciting as hills allow for moves to be made. With a pancake-flat course it is basically a group time trial and takes a lot of the thought out of racing. I also feel like seeing people run up/down hills makes the TV broadcast more engaging.
For reference, I would like to see them race on a course with an average 40-80 ft climbing per mile.