devtrackers.gg
The problem is that AoE increases area not radius to beginn with.
The diameter seems to be somewhere around 10 in the video. Which puts the radius at 5. If we assume 0% inc. AoE used in that video, that 5 would be the base radius.
Now lets add 100% increased area.
First we have to get the base are by using pi*r2 = A
pi*52=78,54 poe square unites
We then get twice the amount of area:
78,54*2=157,08
Now we reverse the area formula
squareroot(A/pi) = r
Which once we added those numbers gives us a radius of 7 or a diameter of 14.
And apparently weapon range is normalized across weapon to 11. With 100% inc aoe you would still be way of from a baseline level 1 weapon range.
With such a low radius you need thousands of inc aoe to get it to "normal" levels of other skills.
That's some cool maths and all, but the base radius of Pestilent Strike is 27, not 5. Both the radius, and the in-game visual effect, are bigger than the red circle drawn on the image shown here. That circle isn't actually indicative of anything.
No amount of optimization can save a skill that's mechanically bad. Divine Ire works because it does have reasonable base AoE, a bit more than twice the radius shown here for Pestilent Strike.
This image does not actually show Pestilent Strike's AoE. That red circle that has been drawn is smaller than the actual effect (both mechanically and visually)