One thought about scaling, and this might not be a problem in later levels (I'm only level 26) but if so I'm not aware of it, but there are some places that FATE's spawn (Memeroon's trading post in Upper La Noscea comes to mind) where there are a lot of people not participating because mining/botany. Given that one of the FATE's there is this huge crab thing, I don't think you'd want it scaling too much from people who aren't even in combat classes. Maybe if it could scale only from the DoW/DoM in the area?