The add effect is high for all the new elemental arrows, on all jobs. On too weak mobs, on my RDM, the add effect was hitting in the 90s. There is a direct proportion between INT and add effect damage, about 1 extra dmg per 1 int. Wearing a Wind Staff will also give an extra boost.
Alla, made a mistake, forgetting Rangers can use it. I know this cause i synthed a stack and used them on RNG lol. The arrows addtional effect (wind) does some crazy damage, as oppsoed to fire, lightning, and ice arrows from past. I noticed addtional effects averaging out in 20-30s damage. No clue if its the same for earth and water, but the wind arrow addtional effect is really nice.
I wonder if we doo all that extra damage with the Wind Arrows because there is so much +wind gear for Ranger. Haven't used them myself and don't really plan to any times soon, but it's a thought.