Discharge and shock is always the opener for deception because its simply more damage. You are eventually going to have to thrash or vs anyways and you have regen boost from dark embrace so why wouldn't you? Let vs be what it is: a boost to your shock damage when you get around to using it.
If you open vs as deception you're just bad, period. There are much better ways to deal damage with your DE regen than to waste it on VS while your regen is 150%.
This is why Wakajinn is such a powerful spec, when Deception Assassins finally start seeing how powerful they can be with out utilizing 2xVS for every single Shock, they will then start noticing that they can drop VS and pick up an ability like DF. The increased crit damage to Thrash via Claws of Decay talent pretty much brings the Thrash ability up to the same damage as VS. So just ask yourself, do you want 30% more damage to Shock, or do you want an instant cast 30m aoe ability that hits almost as hard as Shock to multiple opponents. If you are altering your opening to start off with Shock and Discharge already then you are already playing Wakajinn style. You already forfeited your bonus damage to Shock so you might as well take DF for its awesomeness.