We have 4 of Trixters in the BG. They are 52-53, i.e. has no 55-legendaries and looks fine...
The probability to score zero loses in the Pit Fights for Shadow ~50lvl a bit high than zero. Their domination in the Pit Fights exaggerated. The only relatively viable Shadow-build means Exotic weapon. And Exotics means a very small chance to have right weapon's subtype during Pit Fights.
And i can't believe that counter-attacker may have a troubles vs speeders. Because two rounds enough to bury a speeder, using counter-attack. Considering Dirty Tricks for two rounds, which will be triggered just at the start. Perhaps, Rage-dodgers have chance. But i'm not sure.
I think Power Rages have best chance here. Because (it seems) Dirty Tricks triggers only on "empty" attack, the attack without activates. Power Rage has enough offensive activates. And have greatest damage output too...