Personal test using MNK AF+2, no gear switch, and no main.
Pros: mid-damage weapon skill, has an additional plague effect, damage is consistent.
Cons: Inside abysssea, its a little better than Ascetic's Fury because of the consistent damage. Outside abyssea its a about to a little bit better than Asuran Fist. I wouldn't waste the limited amount of ws merit points on this weapon skill. I would instead spend the points on Resoulution, Requiescat, or Ruinator.
Could try gear swapping some Toci+Headpiece+other dex gear for more damage. But I highly doubt a geared Shijin Spiral can compete with a naked Victory Smite.
- It would be nice to know if you FULLY merited it or not...
How WSC is calcualted[]
Weapon Skill modifiers are calculated based on two numbers. First being the WSC base the second being a multiplier based on the users level.
Per this wiki article Weapon Skill Secondary Attribute Modifier
The help text on the merit WS's lists the WSC value applied after the level alpha of 96 which is 0.85. Thus at 1/5 it would be 20 * 0.85 = 17%. As these weaponskills can only be used by 96+ they will always have a WSC alpha of 0.85.
In contrast a lower level weapon skill like Tachi Gekko has a WSC of 75%. That is the base WSC before level alpha. At 65 Tachi: Gekko would have a final WSC of 75 * .0.88 = 66%, at 75 it would be 75 * 0.83 = 62.25%, at 99 it would be 75 * 0.85 = 63.75%.
For this same reason we list all the merit WS's base WSC to prevent confusion. Listing SS as 17 per merit would have people doing the calculations incorrectly and applying the level correct twice. 5/5 as 100 * 0.85 = 85%, listing it as 85 would be 85 * 0.85 = 72.25 which is incorrect.
I am changing all the merit WS to reflect the standard definition of WSC as expressed by the wiki article on Weapon Skill Damage.