Here's the actual problem with the way this works, especially like that.... people will spend 1 week or so grinding their brains out to get their gear, during which the zone will be bustling. Once people get their gear they will move on and Eureka will become a dead zone where... "Oh, you wanted to spawn and kill NMs? Sorry, your instance only has 20 people in it and they're all doing their own thing. Good luck!" And no one gets Eureka gear again. The zone needed to be a place where SOLO grinding was viable. Having to kill NMs like this to get so many crystals is not feasible for an extended period of time.