They're regular one-time-only quests, so there's no "doing it again" involved. If you've already done it, then you've already done it. Offering the event again would be for people who have NOT yet done it. It's probably the most fun, and certainly the most involved event we've had since ARR launched, and it would be a shame for people who either weren't here or couldn't level up far enough in time to miss out on it.
If they do it again though (perhaps as an anniversary event), I'd hope they adjust the level requirements. Level 13 content shouldn't have a level 45 participation requirement.
