Riot Gas is another potential option that has the advantage of having the perfect CD as well as having a natural extension in the talent tree (just put in a new talent linked to Riot Gas and just swap Ceramic Plating from a 2/4% talent to a straight up 4% talent). Of course, you still have to deal with the amazing uptime of Riot Gas, which means that they benefit can't really be tied to the duration itself. There are 2 possible implementations that I can think of, the first of which is activating Riot Gas provides you with a 3 second buff that increases your F/T Resistance by 100% (i.e. Riot Gas provides you with the baseline effect of Resilience). The second option would be that activating Riot Gas provides you with 1-2 charges of a buff that increases Resistance by 100%. The charges are lost when you mean any of 2 conditions: you leave the area affected by Riot Gas (this also means that it ends when the Riot Gas area fades away) or you successfully resist an F/T attack. Call the talent something like "Dispersal Gas" (i.e there's something in the gas that disperses F/T attacks, such that they fizzle harmlessly rather than hurting you). It might even be interesting if activating Riot Gas applied the same effect to *you and all allies* in the area of the Riot Gas when you activated it (though you'd likely have to limit the charges to 1 per person and reduce the effect to something like 75% F/T damage reduction rather than 100% Resistance; of course, 100% Resistance to allies as well would provide VGs with some very interesting utility and strategic value to ops that they're largely missing now)..
Why not let riot gas give a debuff on all the enemies in its area for them to have -200% accuracy on the next two attacks, of any type? Would be much simplier to implement, and have some very interesting applications in PvP - where they are also currently 3rd rate tanks.