The composition I run that stays in the 20-40 range in arena is...
- Gear12 Zyn(l) working on getting her immune to stun zeta, with R2, CLS, Raid Han(except for his first move), and many other characters running stuns, it a good investment.
- Gear12 zCassian - The zeta is just to make them less squishy, his unique which grants tenacity up at the start of the round to tanks is also really good with the two tanks I use.
- Gear12 zzR2 - He can stun, inflict debuffs which trigger exposes, he can provide a cleanse on critical hits which Cassian and Jyn live off, he also has number crunch to make Jyn an Cassian less squishy, and has smokescreen to divide damage for my following 2 tanks.
- Gear11 Zeb - He dazes on basic (better than K2), his unique recovers so much protection and health, he is the (non zeta) savage opress of the rebels, his basic also stuns those dazed and exposed, so with Jyn, Zeb, and R2 you can stun lock teams easily. He can throw protection up, retribution, and tenacity up which comes in clutch. I have R2 go first on my team and throw smokescreen on him to take the first wave of damage.
Gear10 zOld Ben - Amazing under Jyn, his mind trick lowers TM, throws 2 debuffs which can trigger two exposes on every character, and his taunt with the zeta is amazing, he takes the 2nd and third wave of attacks after Zeb, so I alternate damage between the 2 tanks using smokescreen and taunt.
I just geared my Old Ben to gear 10 yesterday, but once my Old Ben gears up to 11 and 12 and Jyn has her immune to stun Zeta I'm pretty sure I will be in top 20 easy, I find myself losing my Old Ben too fast sometimes due to having low gear(low protection) and not tanking more hits because of it, and because Zyn gets stunned at clutch moments.
I'm also in a Jan 2016 shard.
Jyn's lead exposes so all my character's take advantage of that.
PS. My team find G12 teams with massive protection and health boost easy as I DPS through health percentage.
They hold ok on defense, only falling 20 spots, but again I'm still missing gear levels and a zeta.
Also, against the triple/double cleanse just stun lock the cleansers or TM remove them, Triple cleanse teams are the are the hardest to beat but not impossible. It takes a while to learn how to play with this team but it makes it that much more fun.