I disagree Zanath, but only since Mabinogi EU used the same G1-3 as we currently do. However G1 also rewarded roughly 70-100 AP for completion; it just gives an added incentive to run G1 since it's age is definitely showing at this point due to the quest wait times (irl days for Aeira's books).
It would probably take time to adjust each individual quest too, and it'd be a ultra-low priority I feel.
Trouble is, how would it be approached with regards to those who've already completed it, or elves and giants? Seems unfair to those people.
Simple answer: For every player that has completed the journal entry, they are rewarded for AP. I wouldn't expect every quest to have a reward because doing that would add more work. I agree with you that it's ultra low priority. No other way to put it