Thank you. This is helpful!At this point, Attribute Level mostly affects an adversary's starting Hate score and provides additional Endurance loss when activating Heavy Blow (p.143). It can also serve as a barometer for LMs when building encounters.
If I remember correctly, in TOR1e, Attribute Level was used a lot in special abilities (base and bonus damage and such, like with a Dragon's Fire Breath).
As we get more adversaries in upcoming material, I suspect that Attribute Level will interact in a similar fashion with new Fell Abilities (something I have already begun to employ in my own custom stuff).