Just got Sidious a few hours ago from PvP shipments (not sure if he can be obtained from anything else), and it's been worth the wait. The healing block has proven itself invaluable. I brought him up to level 44, Gear V 4/6, and my first PvP fight of the day was against level 42: Old Ben, Barriss, Lando, Dooku, and Consular. I had Boba, Chewie, Sidious,Talia, and Jawa.http://i.imgur.com/j7tYqQh.pnghttp://i.imgur.com/EciAZqJ.png
Taking the advice others have given, I left Ben for last. I was brought down to Boba and Chewie, but won, thanks to chewie's self heal.
I don't know if it's a thing, but at one point during the fight, Barriss was able to heal through the healing block, or maybe it just dissipated at the same time she healed.