So been playing around on the test server for a while now and while I'm far from posting concrete numbers I have something to give atm.
I did discover some.. interesting things.
Caveat: This is far from a full set of data collection or a really good setup. Just something done quick on the fly. I'm in the process of getting more concrete numbers and I might post it later.
Outside of abyssea: Saromugue (Saru skinks)
Weapon: 90 Hvergelmir
10 ws naked (97int 84str 485atk @ 100% tp) gave averages of 1000
10 ws geared (97base +60int, 84-8 str, 579atk @100%tp gave averages of 882
(I had two odd ones for 1200 and 1300 dmg... crits I'm guessing)
Stacking int brought it down? hmm
Outside of Abyssea: East Ron (rabbits)
Weapon: 90 Hvergelmir
10 ws naked (97int 84str 485atk @ 100% tp) gave averages of 650
10 ws geared (97base +60int, 84-8 str, 579atk @100%tp gave averages of 737
The weaker mobs gave less damage overall.
Abbysea:
20 WS naked (no atmas, no cruor buffs... nada) with 90 Hvergelmir and 97 base int: avg shattersoul dmg was 1210 (rounded up) on Shadow Lizards @ 100% tp
20 WS geared with 90 Hvergelmir and 142 int. (atmas: MM, Kirin, Full Moon + random assortment of what ever int gear I had on at the time.. not a lot honestrly) Avg dmg 1700 on shadow lizards. @ 100%tp
Abyssea was understandably much higher and gave the behavior I expected when adding more int (though base int at the time was lower than when I tested outside. I suspect that the possibility of another modifier might be there.. MAB maybe?)
I have a lot more data that I'm still sifting through and need to test, but here are some quick and dirty numbers. But I can definitely see using this on smn for a damage boost. Especially in abyssea. Assuming the mob you're fighting is still alive after a 3-6k+ BP, this WS will almost certainly finish it off lol.