i think if you ask ross tucker, there's no way he could do it in an actual race. he wasn't all that close when he broke the WR in berlin last year: 3% is a yawning gulf at that level. the breaking2 thing really does require perfect conditions, the pace car allowing him to draft, the track. at least for now.
agree with the perfect conditions part - in terms of weather.
i think if Berlin has perfect conditions, he could actually do it there. but that's a pretty big gamble. With breaking2, they had a window, much better way to do it.
i think he could do it in Berlin tho. His 2:02:37 in London is pure insanity. I imagine that puts him low 2:00's in Berlin, under good weather conditions. Geremew ran the race of his life to get under 2:03. Kipchoge ran smart and turned it up at the end. He's just on a completely different level. IMHO, he only needs pacers for the first half - or a little longer. After that, this guy can get it done running by himself - well, not by himself, he needs the fans cheering at least. As long as he has energy from the crowd, he can do it. He doesn't need other runners. I think he definitely feeds off the crowds though, it keeps him focused/happy.
As for the fitness, it looks like he has it to me. Going 2:00:23? (breaking2) 2:01:37 (berlin) then 2:02:37? (london, holding back) is unreal. This guy doesn't "burn out" / "get content" running at his peak, instead he gets motivated to run faster the next year. Superior mental fitness, his biggest strength IMHO.
Find a clip of Kipchoge running, fresh in a race, good form and strength. Then loop that clip for 2 hours. that's Kipchoge.
But ya sub2 is crazy.. I can't bet against Kipchoge tho, he's an alien.