First of all: does everybody in your team have warmaster/giantslayer as tier 6 mastery? Masteries alone can do millions of damage in the fight.

Your team composition is actually good. But maybe there is still room for some improvement.

Urogrim instead of Kael. Big instead of small poisons, and healing, and he can remove the stun with his A2. Do not use him as teamleader, even if his aura is 1% better than Deacon's. The CB tends to attack the teamleader with his stun hit (unless he has a reason to attack somebody else from weak affinity or lowered health bar). If Urogrim is stunned by himself, he can't remove the stun.

Yeah I know the rules - all of my team has full masteries - all with warmaster. Kael, is mostly to prompt A3 every 4 turns and keep 5% poisons on CB. Urogrim might replace him, but once again - he is totally unbooked, and I am not sure if Urogrim will add more poisons than him. Perhaps it is worth some testing to check differences. Who should I put as lead then? If it is Jareg, he will luse speed tune 4:3 to keep ally protection with stun keeping him on CD. Urogrim is unbooked which meens he cannot cleanse every rotation :/ 

Urogrim is worth 6* and books anyway, even if you not use him in CB. This champ is just insane. The ammount of poison his A3 brings in lvl 25 dungeon waves or DT hard waves will help your account. With very good gear, Urogrim can solo stage 25 dungeons. Tbh, my Urogrim can't solo, I don't have that high end gear. But there are videos on youtube of Urogrim vs. Dragon 25. Build that champ!

That said: If you don't have epic books right now, that would be the case for any epic champ we would suggest. Or are there some epics allready fully booked? If you can't book anybody right now, use your actual team until you have the needed books.

If a booked Urogrim joins instead of Kael, as aura lead I would keep Deacon for his speed aura. Urogrim's speed aura is 1% better, but Urogrim is supposed to cleanse.

For poison, a fully booked Urogrim is slightly better than Kael. 

A3 has 2 big poisons (for Kael: on average) on a 4 turn cooldown for both champs. 

Kael's A1 has a 100% chance to land a small poison, Urogrim's A1 has a 0.16% chance to land 2 poisons, a 0.48% chance to land one poison and a 0.36% chance to land 0 poisons. That is slightly more poison damage than Kael provides, and as these are big poisons, Urogrim pairs better with Venomage.

Okay, so I have another question - who should I book 1st? Venomage or Urogrim? They're both great for CB, and sadly, both are unbooked. Deacon is 50% booked, with A3 fully booked. Jareg has A2 fully booked. The real question is: Veno or Urogrim next with books?

Venomage. He's in your team this second, can keep pairing with Kael if you really need to, and more than that, is a champ we really want to reduce the cooldowns on both the A2 and A3. :)

Do you also reccomend Urogrim as next to 60?