Are you going to say anything of interest or are you just going to attack him?
The problem with the vanguard is that the shield spec is useless in pvp as it only procs on melee and ranged attacks (as opposed to tech and force). To make it worse, when attacked with ranged it's still quite useless as the hits are few in number but strong, making the proc chance derived from the shield something to be laughed at. Its tankability is no match to melee dps classes, as they have enough tools to hold vanguards at the melee's preferred range of engagement rather than the vanguards. The shield mechanic is vastly inferior to bubbles.