Just looking at the Strava on some of my mates that ran the race and the gain is almost 1000 feet throughout the course of the marathon. There don't appear to be any major climbs but the course looks like it moves slightly up and down throughout the race? Can anyone confirm their experience on the course? I know World Records go to die in Berlin but race organizers also invest in that with a small field and pacers versus paying out a bunch of runners for good competition.
What if Chicago only invited 5 big names on each side and brought pacers back? I know Chicago has a bunch of turns but it only gains 200 or 300 ft per Strava. Would that not be a better place to run fast? Might London or Rotterdam be faster?
Your mates' Strava is wrong. I have run Berlin four times now and there is minimal elevation gain. One very slight gradual incline up to the 5 km mark and a small bridge before the 15 km mark that I can think of and really nothing else. I would say 200 to 300 feet sounds about right. It feels absolutely flat. And the asphalt seems faster than other courses I've run. Plus, the crowd is amazing and covers almost 100 % of the course. London is great at points but there are parts where you run without fans. Can't compare to Boston.
There probably is some faster course purely going by the route somewhere (think I read Poland?). But considering fans and competition, Berlin has to be the fastest overall (you're probably better off running with other fast people than on a slightly faster course somewhere in nowhere) and for sure the fastest Major.