The first way you can fix the sound effects during fates and such is to allow for a filter which only plays basic sounds like Attack hits, Spell casts,buffs/debuffs for all none party member players. I hear it more with rage of halon then anything. Rage of Halon's sound effect is loud and stands out from the rest of the other sound effects. But I also think attack skills and buffs need to be simplified just for open world none party memebers. For yourself and your party members you can hear the regular sound effects.