No Mithrala? Or did you save the summoning for a CvC? Mithrala is totally insane in the arena. She is basically immune to debuffs on her own (exept Ronda's unresitable block skills) and can cleanse. That alone, even without her hex + petrification, would be worth 6*. 

Another champ I would definetly max is Coldheart. Stage 20 dungeons are the best for tournaments (points/energy ratio), and up to stage 20 damage based on enemy max hp has no cap. 

Champs you are sleeping on and which are worth bringing up to 60 in my opinion:

Aox, Toragi, Mordecai, Coldheart, UDK, Fenax, Skathix, Visix

Champs I would have leveled differently: You leveled up your champs...no sense in retroactively talking about mistakes

CH for sure I know I've definitely been tripping not maxxing her. What's worse is she's built, all masteries and booked. She still hits the 7xx,xxx dmg cap on spider but on later stages doesn't even get a turn 😂 

What are you running for Spider, CB right now?