So me and my friend were talking about how lancer/dragoon get no proc or circumstantial moves, e.g shield swipe, haymaker, mercy stroke, misery's end.
So I thought a good move for lancer would be sudden lunge. After a successful parry you can deliver an attack with ??(whatever's balanced) potency. Additional effect terror. Duration 3 seconds.
Basically the idea was this could be used to make keen flurry more useful to lancer and the terror would give the lancer a chance when solo to move to the mobs flank for a heavy thrust or behind for an impulse drive. I opted not to use stun as the add effect cause lancer already had leg sweep and this way it wouldn't build the enemies stun resistance. 3 second duration would mean it would last long enough for your GCD to reset after using it and just enough time to use a heavy thrust or impulse drive before it wears off.