To be fair they did say that Diadem was an experiment. I think it's a matter of content being designed for the Japanese side of the fence and working out successfully there but not working out on our side of the fence. On Japanese servers when a Hunt pops there's a lot of people waiting patiently and not abusing the system/pulling early due to impatience. Over here you're lucky if you get five minutes to head to a Hunt once it's been spotted by a party tracking them down.