Grand Moff Tarkin is pathetic.

"Telos;837031" wrote:

"Allenb60;837005" wrote:

Hey it's a 55% chance if you upgrade his ship, and his ship's crew ability also allows the largest damage bonus

Even so, the ability remains largely unreliable - you need to get very lucky in order for it debuff the right targets or even land on all five. The ability directly ties in to your second point, his crew ability. To my knowledge, it's the only ability in your arsenal which can aoe debuff, which is highly required for his crew ability. You don't have time to go around debuffing everyone separately before going in (and thus maximizing the damage gain), you want to start taking out their good ships asap.

So as I said before, the only way the Executrix reigns superior is on a Ion Cannon high-roll, ability blocking all five enemies and, as you mentioned, vastly increasing the damage of your ships. He can shine, but it is a rare occurrence.