I'd love to be able to unsync it, just go into Anemos EL60 ILvl 450 or whatever and just run around and splatter enemies. 500k damage, 700k damage. Just run into the Paz Cave and "take that" Wraith, "Take that and that. Yea remember when you one shotted me? Well how do you like it now" I don't think that would ever get old. Then move into Pagos..."Oh hello Dragon. Remember me?"
Doubt it will happen though. More likely they may up the Ilvl sync and lower enemy hp. Will be hard though as many of the higher end fates in all Eurekas (from Paz and Amerok to Skoll and Cassie) would be hard to do even then with just a handful of people. if it becomes like past relics where there might be a few people on each server working on the same step as you. I wouldn't be surprised to see less than 20 in eureka at a time. Unless they remove the delevel aspect that's asking for issues. As for BA, that might be lucky to get 1 clear a month, dare I say a year depending on how hard Eureka drops off.
