make it can only be consumed by the time rather than dmg since when facing powerful npcs and players it will make you get into haki overuse too early(instead there could be a lasting time for it just like aura) compared to other hakis
whats more,make future sight counter future sight if there will be no kenbunshoku killing(or kenbunshoku killing has a better effect like also cannot be observed by aura and hostile mobs?)