Sigma
The damage increase to Army ghouls is very substantial; it's not visible in data, but it will be apparent right away upon trying it out.
If the goal is ensuring Festering Strike is always a priority to use, buffing Festering Strike and Festering Wound should both work; we did some of both (moreso Festering Wound). At this point, the damage of a Festering Strike plus 3 Festering Wound bursts should be quite a bit higher than that of 2 Clawing Shadows--if this isn't the case, please let us know the builds/situations where it appears that Festering Strike is not worth the Rune cost and we'll examine further.