taking a turn to heal is the last thing you want to do i n the arena at higher levels. JC should be out even if he's g10 or 11. More useful abilities are TM control, debuffs including ability block, etc. DV should have been able to strike him down with culling blade or else you need more characters that do more damage than JC. I'm not certain how much damage Talia brings but there's synergy from NS. The other thing you could do is use DV lead with another Empire/Sith to take advantage of Vader Offense/TM.