On the Live servers, Shadowy Disguise is a good skill for PvE Nightblades because it procs Born From Shadow (increasing damage done to monsters by 10%), Shadow Barrier (granting Major Resolve), and Strike from the Shadows for Vampires (increasing Weapon and Spell Damage by 300).
However, on the PTS certain skills now prevent you from casting Shadowy Disguise while they're active, such as Banner Bearer and Shalks. While this makes sense in PvP, it's a direct nerf to pure Nightblade PvE setups that currently use Banner Bearer. It also makes the Shadow skill line even less appealing for subclassing as well, because the highest parsing setups on the PTS I've seen all seem to use Banner Bearer now.
Would it please be possible to change Shadowy Disguise so that it can always be activated to trigger its associated buffs, but that it's immediately deactivated if an ability that suppresses Sneaking or Invisibility is active or something? That seems like a nice QOL change for PvE to me.
(And to make the Shadow skill line more desirable in PvE, perhaps the Born From Shadow buff could be increased a bit to make up for the lack of offensive passives in the skill line? That would be a nice buff for pure Nightblades too.)