The effect is a slight darkness around your character... But the effect is so small that your character model eclipses most of it. Also, if you have a DoT effect on you, that visual over rides the duplicity effect.
Essentially forcing you to look for a reddish black buff box on your buff bar... But there's several of those. Pvp Exp buff, AP stim, Might, several others.
So you almost have to just stare at your buff bar to optimize your damage output / energy use. In pvp? That's stupid. Beyond belief.
I agree thats a bit absurd. I don't have to stare at my bar because I see my Barrage proc on my Merc due to the animation. They do need to change it because the current version only promotes tunneling.
That's the buff that looks like the red saber, yea? I was not a fan of the lack of visual but now I know what the buff on the bar looks like so it's all good. Would appreciate some sort of grand visual effect, though.