It's interesting this change. I have noticed that it is a little trickier to zoom around traya squads (I run traya too) but I've worked out a strategy to get me past the Sion + Sith trooper combo.
Use thrawn to fracture Sith trooper. Your Sion to put pain and Nihilus to drain/increase cooldowns. Then traya to isolate Sion (no more taunt). Thrawn to boost Nihilus to his 2nd drain then immediately fracture Sith trooper. Now their Nihilus is open to be annihilated.
Works everytime (80% of the time) ?