How at all can Empyreal Arrow be seen coming?
With Between the Eyes you know it's coming if you get CC'd by the Machinist. I've been against players like Straigus Reyist that are able to completely shut down my Between the Eyes.
In regards to "no pre-requisites" I meant that the target doesn't have to be afflicted by a certain action in order for you to use it. Wanderers Minuet should be up anyway just like Gauss Barrel.
My intention was not to turn this discussion into "Bard vs. Machinist" but rather to point out that 6500 damage from a single attack is insane and I know many fellow PVPers who agree with this.