Nihilus team comp

I know i am not lvl 80 and havent play high ranked game yet, I'm only 60 but...

I play Nihilus as my leader, with Vader, Sidious, Sith Trooper and oftenly Dooku, and this rock hard.
Except against someone who got an Heal Immune, Sith trooper with retaliation + taunt + heal (around 85% with my Nihilus how it is now) and I go against 2 or 3k power more team in Arena. Sith Trooper oftenly dies, but not after took an incredible amount of damage.

All the AoE makes super efficient heal when you need it (Sidious + Vader + Nihilus + Sith Trooper), Stun with Dooku. Attacking Dooku means counter attack means counter heal, means it's almost useless. With all those DoT, Vader execution is super strong (try it on a 5 dot-ed target. I insta kill one guy with 90% life), and Nihilus is an incredible support to your DoT, and can be a monster when you get annihilation (which is really fast, as you have around 3 effects on each target).

But still, I'm a newbie, so perhaps what I see at my level is clearly wrong in High Level.