I noticed that the AOE skill Whirlwind can't crit from sneak attacks. They CAN crit, but only from normal use.
As you can see here, I sneaked behind some mudcrabs to test the whirlwind sneak attack.
Aaaaand... nope! Lame, unnoticeable damage numbers appeared instead.
So I tried again with Shadowy Disguise this time. It explicitly states you get +100% crit rate during the duration. You can even see this in you stats. I've tried it using normal hits, other weapon skills and yes they're guaranteed crit... But not Whirlwind!
The increased damage actually came form the execute bonus, not crit. If they crit it will show a "*" next to the numbers. Like this:
So they CAN crit, but just not during sneak, which is really weird.
I thought to myself, "maybe it's because it's an AOE?" but then I saw that Lotus Fan DOES crit from sneak attack. So there's no reason as to why Whirldwind shouldn't be able to crit, at least let Shadowy Disguise do its job.
If they fixes this, this could really buff up this skill line and NB in general.
Power Extraction/Sap Essence + Shadowy Disguise + Whirlwind combo for guaranteed AOE crit could really wreck enemies.